diff --git a/MaiChartManager/Controllers/Charts/ChartController.cs b/MaiChartManager/Controllers/Charts/ChartController.cs
index 91a726a..a802a63 100644
--- a/MaiChartManager/Controllers/Charts/ChartController.cs
+++ b/MaiChartManager/Controllers/Charts/ChartController.cs
@@ -95,15 +95,29 @@ public void EditChartEnable(int id, int level, [FromBody] bool value, string ass
     }
 
     [HttpPost]
-    public void ReplaceChart(int id, int level, IFormFile file, string assetDir)
+    public void ReplaceChart(int id, int level, IFormFile file, string assetDir, 
+        [FromForm] ImportChartController.ShiftMethod? shift)
     {
         var music = settings.GetMusic(id, assetDir);
         if (music == null || file == null) return;
+        // TODO 判断是MA2还是maidata.txt，走不同的逻辑
         var targetChart = music.Charts[level];
         targetChart.Path = $"{id:000000}_0{level}.ma2";
         using var stream = System.IO.File.Open(Path.Combine(StaticSettings.StreamingAssets, assetDir, "music", $"music{id:000000}", targetChart.Path), FileMode.Create);
         file.CopyTo(stream);
         targetChart.Problems.Clear();
         stream.Close();
+        
+        // 检查新谱面ma2的音符数量是否有变化，如果有修正之
+        string fileContent;
+        using (var reader = new StreamReader(file.OpenReadStream()))
+        {
+            fileContent = reader.ReadToEnd();
+        }
+        var newMaxNotes = ImportChartController.ParseTNumAllFromMa2(fileContent);
+        if (newMaxNotes != 0 && targetChart.MaxNotes != newMaxNotes)
+        {
+            targetChart.MaxNotes = newMaxNotes;
+        }
     }
 }
\ No newline at end of file
diff --git a/MaiChartManager/Controllers/Charts/ImportChartController.cs b/MaiChartManager/Controllers/Charts/ImportChartController.cs
index 20bf25a..5776969 100644
--- a/MaiChartManager/Controllers/Charts/ImportChartController.cs
+++ b/MaiChartManager/Controllers/Charts/ImportChartController.cs
@@ -191,11 +191,18 @@ public record ImportChartMessage(string Message, MessageLevel Level);
     public record ImportChartCheckResult(bool Accept, IEnumerable<ImportChartMessage> Errors, float MusicPadding, bool IsDx, string? Title, float first, float bar);
 
     [HttpPost]
-    public ImportChartCheckResult ImportChartCheck(IFormFile file)
+    public ImportChartCheckResult ImportChartCheck(IFormFile file, [FromForm] bool isReplacement = false)
     {
         var errors = new List<ImportChartMessage>();
         var fatal = false;
 
+        if (isReplacement)
+        {
+            // 替换谱面的操作也需要检查的过程，但检查的逻辑和导入谱面时可以说是一模一样的，故直接共用逻辑
+            // 唯一的区别是给用户一个警告，明确说明直接替换谱面功能的适用范围
+            errors.Add(new ImportChartMessage(Locale.NotesReplacementWarning, MessageLevel.Warning));
+        }
+
         try
         {
             var kvps = new SimaiFile(file.OpenReadStream()).ToKeyValuePairs();
@@ -559,6 +566,7 @@ public ImportChartResult ImportChart(
         music.AddVersionId = addVersionId;
         music.GenreId = genreId;
         music.Version = version;
+        music.ShiftMethod = shift.ToString();
         float wholebpm;
         if (float.TryParse(maiData.GetValueOrDefault("wholebpm"), out wholebpm))
             music.Bpm = wholebpm;
@@ -568,7 +576,7 @@ public ImportChartResult ImportChart(
     }
 
 
-    private static int ParseTNumAllFromMa2(string ma2Content)
+    public static int ParseTNumAllFromMa2(string ma2Content)
     {
         var lines = ma2Content.Split('\n');
         // 从后往前读取，因为 T_NUM_ALL 在文件最后
diff --git a/MaiChartManager/Front/src/client/apiGen.ts b/MaiChartManager/Front/src/client/apiGen.ts
index c0aa133..7fe258b 100644
--- a/MaiChartManager/Front/src/client/apiGen.ts
+++ b/MaiChartManager/Front/src/client/apiGen.ts
@@ -266,6 +266,7 @@ export interface MusicXmlWithABJacket {
   subLockType?: number;
   disable?: boolean;
   longMusic?: boolean;
+  shiftMethod?: string | null;
   charts?: Chart[] | null;
   assetBundleJacket?: string | null;
   pseudoAssetBundleJacket?: string | null;
@@ -965,6 +966,7 @@ export class Api<SecurityDataType extends unknown> extends HttpClient<SecurityDa
       data: {
         /** @format binary */
         file?: File;
+        shift?: ShiftMethod;
       },
       params: RequestParams = {},
     ) =>
@@ -1236,6 +1238,8 @@ export class Api<SecurityDataType extends unknown> extends HttpClient<SecurityDa
       data: {
         /** @format binary */
         file?: File;
+        /** @default false */
+        isReplacement?: boolean;
       },
       params: RequestParams = {},
     ) =>
diff --git a/MaiChartManager/Front/src/components/DragDropDispatcher/ReplaceChartModal.tsx b/MaiChartManager/Front/src/components/DragDropDispatcher/ReplaceChartModal.tsx
index a0cbf59..06fb0ae 100644
--- a/MaiChartManager/Front/src/components/DragDropDispatcher/ReplaceChartModal.tsx
+++ b/MaiChartManager/Front/src/components/DragDropDispatcher/ReplaceChartModal.tsx
@@ -1,24 +1,68 @@
 import { t } from '@/locales';
 import { globalCapture, selectedADir, selectedLevel, selectedMusic, selectMusicId, updateMusicList } from '@/store/refs';
-import { NButton, NFlex, NModal, useMessage } from 'naive-ui';
-import { defineComponent, PropType, ref, computed, watch, shallowRef } from 'vue';
+import { NButton, NFlex, NModal, useDialog, useMessage } from 'naive-ui';
+import { defineComponent, ref, shallowRef } from 'vue';
 import JacketBox from '../JacketBox';
 import { DIFFICULTY, LEVEL_COLOR } from '@/consts';
 import api from '@/client/api';
+import CheckingModal from "@/components/ImportCreateChartButton/ImportChartButton/CheckingModal";
 
-export const replaceChartFileHandle = shallowRef<FileSystemFileHandle | null>(null);
+export let prepareReplaceChart = async (fileHandle?: FileSystemFileHandle) => {
+}
 
 export default defineComponent({
   // props: {
   // },
   setup(props, { emit }) {
     const message = useMessage();
+    const dialog = useDialog();
 
-    const replaceChart = async () => {
-      if (!replaceChartFileHandle.value) return;
+    const checking = ref(false);
+    const ma2Handle = shallowRef<FileSystemFileHandle | null>(null);
+
+    prepareReplaceChart = async (fileHandle?: FileSystemFileHandle) => {
+      if (!fileHandle) {
+        [fileHandle] = await window.showOpenFilePicker({
+          id: 'chart',
+          startIn: 'downloads',
+          types: [
+            {
+              description: t('music.edit.supportedFileTypes'),
+              accept: {
+                "application/x-supported": [".ma2", ".txt"], // 没办法限定只匹配maidata.txt，就只好先把一切txt都作为匹配
+              },
+            },
+          ],
+        });
+      }
+      if (!fileHandle) return; // 用户未选择文件
+
+      const name = fileHandle.name;
+      // 对maidata.txt和ma2分类讨论，前者执行ImportCheck
+      if (name == "maidata.txt") {
+        try {
+          checking.value = true;
+          const file = await fileHandle.getFile();
+          const checkRet = (await api.ImportChartCheck({file, isReplacement: true})).data;
+          if (!checking.value) return; // 说明检查期间用户点击了关闭按钮、取消了操作。则不再执行后续流程。
+          // TODO 显示导入界面（类似ErrorDisplayIdInput）、完成导入流程
+          console.log(checkRet)
+          dialog.error({title: "NotImplemented"})
+        } finally {
+          checking.value = false;
+        }
+      } else if (name.endsWith(".ma2")) {
+        ma2Handle.value = fileHandle
+      } else {
+        dialog.error({title: t('error.unsupportedFileType'), content: t('music.edit.notValidChartFile')})
+      }
+    }
+
+    const replaceMa2 = async () => {
+      if (!ma2Handle.value) return;
       try {
-        const file = await replaceChartFileHandle.value.getFile();
-        replaceChartFileHandle.value = null;
+        const file = await ma2Handle.value.getFile();
+        ma2Handle.value = null;
         await api.ReplaceChart(selectMusicId.value, selectedLevel.value, selectedADir.value, { file });
         message.success(t('music.edit.replaceChartSuccess'));
         await updateMusicList();
@@ -28,34 +72,37 @@ export default defineComponent({
       }
     }
 
-    return () => <NModal
-      preset="card"
-      class="w-[min(90vw,50em)]"
-      title={t('music.edit.replaceChart')}
-      show={replaceChartFileHandle.value !== null}
-      onUpdateShow={() => replaceChartFileHandle.value = null}
-    >{{
-      default: () => <div class="flex flex-col gap-2">
-        {t('music.edit.replaceChartConfirm', { level: DIFFICULTY[selectedLevel.value!] })}
-        <div class="text-4.5 text-center">{replaceChartFileHandle.value?.name}</div>
-        <div class="text-6 text-center">↓</div>
-        <div class="flex justify-center gap-2">
-          <JacketBox info={selectedMusic.value!} class="h-8em w-8em" upload={false} />
-          <div class="flex flex-col gap-1 max-w-24em justify-end">
-            <div class="text-3.5 op-70">#{selectMusicId.value}</div>
-            <div class="text-2xl overflow-hidden text-ellipsis whitespace-nowrap">{selectedMusic.value!.name}</div>
-            <div class="flex">
-              <div class="c-white rounded-full px-2" style={{ backgroundColor: LEVEL_COLOR[selectedLevel.value!] }}>
-                {selectedMusic.value!.charts![selectedLevel.value!]?.level}.{selectedMusic.value!.charts![selectedLevel.value!]?.levelDecimal}
+    return () => <div>
+        <NModal
+        preset="card"
+        class="w-[min(90vw,50em)]"
+        title={t('music.edit.replaceChart')}
+        show={ma2Handle.value !== null}
+        onUpdateShow={() => ma2Handle.value = null}
+      >{{
+        default: () => <div class="flex flex-col gap-2">
+          {t('music.edit.replaceChartConfirm', { level: DIFFICULTY[selectedLevel.value!] })}
+          <div class="text-4.5 text-center">{ma2Handle.value?.name}</div>
+          <div class="text-6 text-center">↓</div>
+          <div class="flex justify-center gap-2">
+            <JacketBox info={selectedMusic.value!} class="h-8em w-8em" upload={false} />
+            <div class="flex flex-col gap-1 max-w-24em justify-end">
+              <div class="text-3.5 op-70">#{selectMusicId.value}</div>
+              <div class="text-2xl overflow-hidden text-ellipsis whitespace-nowrap">{selectedMusic.value!.name}</div>
+              <div class="flex">
+                <div class="c-white rounded-full px-2" style={{ backgroundColor: LEVEL_COLOR[selectedLevel.value!] }}>
+                  {selectedMusic.value!.charts![selectedLevel.value!]?.level}.{selectedMusic.value!.charts![selectedLevel.value!]?.levelDecimal}
+                </div>
               </div>
             </div>
           </div>
-        </div>
-      </div>,
-      footer: () => <NFlex justify="end">
-        <NButton onClick={() => replaceChartFileHandle.value = null}>{t('common.cancel')}</NButton>
-        <NButton onClick={replaceChart} type="primary">{t('common.confirm')}</NButton>
-      </NFlex>
-    }}</NModal>;
+        </div>,
+        footer: () => <NFlex justify="end">
+          <NButton onClick={() => ma2Handle.value = null}>{t('common.cancel')}</NButton>
+          <NButton onClick={replaceMa2} type="primary">{t('common.confirm')}</NButton>
+        </NFlex>
+      }}</NModal>
+      <CheckingModal title={t('chart.import.checkingTitle')} show={checking.value} closeModal={()=>checking.value=false} />
+    </div>;
   },
 });
diff --git a/MaiChartManager/Front/src/components/DragDropDispatcher/index.tsx b/MaiChartManager/Front/src/components/DragDropDispatcher/index.tsx
index 86e0d7e..3cb9fb5 100644
--- a/MaiChartManager/Front/src/components/DragDropDispatcher/index.tsx
+++ b/MaiChartManager/Front/src/components/DragDropDispatcher/index.tsx
@@ -5,7 +5,7 @@ import { uploadFlow as uploadFlowMovie } from '@/components/MusicEdit/SetMovieBu
 import { uploadFlow as uploadFlowAcbAwb } from '@/components/MusicEdit/AcbAwb';
 import { selectedADir, selectedMusic } from '@/store/refs';
 import { upload as uploadJacket } from '@/components/JacketBox';
-import ReplaceChartModal, { replaceChartFileHandle } from './ReplaceChartModal';
+import ReplaceChartModal, { prepareReplaceChart } from './ReplaceChartModal';
 import AquaMaiManualInstaller, { setManualInstallAquaMai } from './AquaMaiManualInstaller';
 
 export const mainDivRef = shallowRef<HTMLDivElement>();
@@ -48,8 +48,8 @@ export default defineComponent({
         else if (file.kind === 'file' && (firstType.startsWith('image/') || file.name.endsWith('.jpeg') || file.name.endsWith('.jpg') || file.name.endsWith('.png'))) {
           uploadJacket(file);
         }
-        else if (file.kind === 'file' && file.name.endsWith('.ma2')) {
-          replaceChartFileHandle.value = file;
+        else if (file.kind === 'file' && (file.name.endsWith('.ma2') || file.name == "maidata.txt")) {
+          prepareReplaceChart(file);
         }
       }
     }
diff --git a/MaiChartManager/Front/src/components/MusicEdit/ChartPanel.tsx b/MaiChartManager/Front/src/components/MusicEdit/ChartPanel.tsx
index 1fd51cf..c780e60 100644
--- a/MaiChartManager/Front/src/components/MusicEdit/ChartPanel.tsx
+++ b/MaiChartManager/Front/src/components/MusicEdit/ChartPanel.tsx
@@ -1,12 +1,13 @@
 import { computed, defineComponent, PropType, watch } from "vue";
 import { Chart } from "@/client/apiGen";
-import { NFlex, NForm, NFormItem, NInput, NInputNumber, NSelect, NSwitch } from "naive-ui";
+import { NButton, NFlex, NForm, NFormItem, NInput, NInputNumber, NSelect, NSwitch } from "naive-ui";
 import api from "@/client/api";
 import { selectedADir, selectedMusic } from "@/store/refs";
 import { LEVELS } from "@/consts";
 import ProblemsDisplay from "@/components/ProblemsDisplay";
 import PreviewChartButton from "@/components/MusicEdit/PreviewChartButton";
 import { useI18n } from 'vue-i18n';
+import { prepareReplaceChart } from "@/components/DragDropDispatcher/ReplaceChartModal";
 
 const LEVELS_OPTIONS = LEVELS.map((level, index) => ({label: level, value: index}));
 
@@ -43,6 +44,9 @@ export default defineComponent({
       <NFlex vertical>
         <NFlex align="center" class="absolute right-0 top-0 m-xy mt-2 z-2">
           <PreviewChartButton songId={props.songId} level={props.chartIndex}/>
+          <NButton secondary onClick={() => prepareReplaceChart()}>
+            {t('music.edit.replaceChart')}
+          </NButton>
         </NFlex>
         <NFormItem label={t('music.edit.chartEnable')} labelPlacement="left" class="ml-2px">
           <NFlex align="center">
diff --git a/MaiChartManager/Front/src/locales/en.yaml b/MaiChartManager/Front/src/locales/en.yaml
index 8dd7b27..75f5943 100644
--- a/MaiChartManager/Front/src/locales/en.yaml
+++ b/MaiChartManager/Front/src/locales/en.yaml
@@ -133,6 +133,7 @@ music:
     replaceChartConfirm: Confirm to replace {level}?
     replaceChartFailed: Failed to replace chart
     replaceChartSuccess: Chart replaced successfully
+    notValidChartFile: Chart file must be .ma2 or maidata.txt.
   batch:
     title: Batch Actions
     batchAndSearch: Batch Actions & Search
@@ -456,6 +457,7 @@ error:
     confirm: Got it
   file:
     notSelected: No file selected
+  unsupportedFileType: 'Unsupported file type'
 message:
   notice: Notice
   saveSuccess: Saved successfully
diff --git a/MaiChartManager/Front/src/locales/zh-TW.yaml b/MaiChartManager/Front/src/locales/zh-TW.yaml
index da16da8..49fdaf7 100644
--- a/MaiChartManager/Front/src/locales/zh-TW.yaml
+++ b/MaiChartManager/Front/src/locales/zh-TW.yaml
@@ -126,6 +126,7 @@ music:
     replaceChartConfirm: 確認要替換 {level} 譜面嗎？
     replaceChartFailed: 替換譜面失敗
     replaceChartSuccess: 替換譜面成功
+    notValidChartFile: 譜面檔案必須是 .ma2 或 maidata.txt。
   batch:
     title: 批次操作
     batchAndSearch: 批次操作與搜尋
@@ -417,6 +418,7 @@ error:
   feedbackError: 回饋錯誤
   file:
     notSelected: 未選擇檔案
+  unsupportedFileType: '不支援的檔案類型'
 message:
   notice: 提示
   saveSuccess: 儲存成功
diff --git a/MaiChartManager/Front/src/locales/zh.yaml b/MaiChartManager/Front/src/locales/zh.yaml
index f9c02ec..05b10a8 100644
--- a/MaiChartManager/Front/src/locales/zh.yaml
+++ b/MaiChartManager/Front/src/locales/zh.yaml
@@ -126,6 +126,7 @@ music:
     replaceChartConfirm: 确认要替换 {level} 谱面吗？
     replaceChartFailed: 替换谱面失败
     replaceChartSuccess: 替换谱面成功
+    notValidChartFile: 谱面文件必须是.ma2或maidata.txt
   batch:
     title: 批量操作
     batchAndSearch: 批量操作与搜索
@@ -418,6 +419,7 @@ error:
   feedbackError: 反馈错误
   file:
     notSelected: 未选择文件
+  unsupportedFileType: 不支持的文件类型
 message:
   notice: 提示
   saveSuccess: 保存成功
diff --git a/MaiChartManager/Locale.Designer.cs b/MaiChartManager/Locale.Designer.cs
index 98c5e49..4961999 100644
--- a/MaiChartManager/Locale.Designer.cs
+++ b/MaiChartManager/Locale.Designer.cs
@@ -630,6 +630,15 @@ internal static string MusicNoTitle {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Caution! This &quot;Replace Chart&quot; function should only be used when modifying the note content of the existing chart, while the audio remains unchanged, the &amp;first offset remains unchanged, and the timing of the first note remains unchanged. Otherwise, you will need to delete the entire chart and re-import it..
+        /// </summary>
+        internal static string NotesReplacementWarning {
+            get {
+                return ResourceManager.GetString("NotesReplacementWarning", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Please enter activation code.
         /// </summary>
diff --git a/MaiChartManager/Locale.resx b/MaiChartManager/Locale.resx
index 20f9e43..b89915e 100644
--- a/MaiChartManager/Locale.resx
+++ b/MaiChartManager/Locale.resx
@@ -293,4 +293,7 @@ If you notice any issues with the conversion result, you can try testing it in A
     <data name="LauncherOpenToLanDesc" xml:space="preserve">
       <value>Automatically run in server mode and minimize to the system tray upon startup.</value>
     </data>
+    <data name="NotesReplacementWarning" xml:space="preserve">
+      <value>Caution! This "Replace Chart" function should only be used when modifying the note content of the existing chart, while the audio remains unchanged, the &amp;first offset remains unchanged, and the timing of the first note remains unchanged. Otherwise, you will need to delete the entire chart and re-import it.</value>
+    </data>
 </root>
\ No newline at end of file
diff --git a/MaiChartManager/Locale.zh-hans.resx b/MaiChartManager/Locale.zh-hans.resx
index f6ddf3c..810a0f5 100644
--- a/MaiChartManager/Locale.zh-hans.resx
+++ b/MaiChartManager/Locale.zh-hans.resx
@@ -285,4 +285,7 @@
     <data name="LauncherOpenToLanDesc" xml:space="preserve">
       <value>开机自动以服务器模式运行并最小化到托盘</value>
     </data>
+    <data name="NotesReplacementWarning" xml:space="preserve">
+      <value>注意！本“替换谱面”功能仅限用于：谱面音符内容在原来的基础上发生修改，且音频内容未变、&amp;first偏移量未变、谱面中第一个音符的时刻未变的情况。否则，您需要删除整个谱面后重新导入。</value>
+    </data>
 </root>
\ No newline at end of file
diff --git a/MaiChartManager/Locale.zh-hant.resx b/MaiChartManager/Locale.zh-hant.resx
index 91b66db..c1282c2 100644
--- a/MaiChartManager/Locale.zh-hant.resx
+++ b/MaiChartManager/Locale.zh-hant.resx
@@ -285,4 +285,7 @@
     <data name="LauncherOpenToLanDesc" xml:space="preserve">
       <value>開機自動以伺服器模式運作並最小化到托盤</value>
     </data>
+    <data name="NotesReplacementWarning" xml:space="preserve">
+      <value>>請注意！本「替換譜面」功能僅限用於：譜面音符內容在原來的基礎上發生修改，且音訊內容未變、&amp;first偏移量未變、譜面中第一個音符的時刻未變的情況。否則，您需要刪除整個譜面後重新匯入。</value>
+    </data>
 </root>
\ No newline at end of file
diff --git a/MaiChartManager/Models/MusicXml.cs b/MaiChartManager/Models/MusicXml.cs
index 86f6da8..7136519 100644
--- a/MaiChartManager/Models/MusicXml.cs
+++ b/MaiChartManager/Models/MusicXml.cs
@@ -377,16 +377,7 @@ public string UtageKanji
         set
         {
             Modified = true;
-            var node = RootNode.SelectSingleNode(utageKanjiNode);
-            if (node is null)
-            {
-                node = xmlDoc.CreateNode(XmlNodeType.Element, utageKanjiNode, null);
-                node.InnerText = value;
-                RootNode.AppendChild(node);
-                return;
-            }
-
-            RootNode.SelectSingleNode(utageKanjiNode).InnerText = value;
+            SelectSingleNodeOrCreate(RootNode, utageKanjiNode).InnerText = value;
         }
     }
 
@@ -398,16 +389,7 @@ public string Comment
         set
         {
             Modified = true;
-            var node = RootNode.SelectSingleNode(commentNode);
-            if (node is null)
-            {
-                node = xmlDoc.CreateNode(XmlNodeType.Element, commentNode, null);
-                node.InnerText = value;
-                RootNode.AppendChild(node);
-                return;
-            }
-
-            RootNode.SelectSingleNode(commentNode).InnerText = value;
+            SelectSingleNodeOrCreate(RootNode, commentNode).InnerText = value;
         }
     }
 
@@ -466,6 +448,18 @@ public bool LongMusic
             node.InnerText = value ? "1" : "0";
         }
     }
+    
+    // 以下是游戏本体不会使用、而是由MCM使用的扩展字段，统一放到"X-MCM"下。
+    
+    public string ShiftMethod
+    {
+        get => RootNode.SelectSingleNode("X-MCM/shiftMethod")?.InnerText;
+        set
+        {
+            Modified = true;
+            SelectSingleNodeOrCreate(RootNode, "X-MCM/shiftMethod").InnerText = value;
+        }
+    }
 
     public class Chart
     {
@@ -571,4 +565,22 @@ public void Save()
         Modified = false;
         xmlDoc.Save(FilePath);
     }
+
+    private XmlNode SelectSingleNodeOrCreate(XmlNode parent, string xpath)
+    {
+        var node = parent.SelectSingleNode(xpath);
+        if (node is not null) return node;
+        // 由于xmlDoc.CreateNode不支持xpath，因此当xpath有多层时，必须对每一层依次分别创建
+        foreach (var s in xpath.Split('/'))
+        {
+            node = parent.SelectSingleNode(s);
+            if (node is null)
+            {
+                node = xmlDoc.CreateNode(XmlNodeType.Element, s, null);
+                parent.AppendChild(node);
+            }
+            parent = node; // 继续下一层的处理
+        }
+        return node;
+    }
 }
\ No newline at end of file