diff --git a/docs/29-全项目审计.md b/docs/29-全项目审计.md
index 6fbb10e..671cda9 100644
--- a/docs/29-全项目审计.md
+++ b/docs/29-全项目审计.md
@@ -132,6 +132,13 @@ src-tauri/src/ 全部（1289 行）。先说结论：发现 **1 个高危数据
 - D1（中）非 UTF-8 文件首次保存被静默转码为 UTF-8（GBK/UTF-16
   文档存一次即变 UTF-8）：编辑器内部统一 UTF-8 是既定设计，但
   落盘编码变更应至少首次提示一次。需前端交互拍板，未擅自加。
+  → **已于当晚按用户拍板实现**：saveTab 在落盘前拦截，首次保存
+  弹 EncodingConvertModal 说明将转 UTF-8（按路径记已确认、本次
+  运行只提示一次）；自动保存不弹窗也不静默转码，跳过该文档等
+  手动保存时提示；确认后以冻结快照完成落盘，标签 encoding 如实
+  更新为 UTF-8。弹窗渲染置于所有弹窗之后（避免被关窗确认框
+  盖住）。vitest 123+2（含弹窗契约测试）。真机验证点：拿一个
+  GBK 文档改字后 Ctrl+S，应先弹提示、确认后才落盘。
 - D2（中）专注模式跨块时全量重建装饰集：大文档每次回车重建与
   顶层块数等量的装饰对象。改增量方案需重构插件，单独立项。
 - D3（低）源码模式每次击键物化全文回写 App（无渲染模式的 200ms
diff --git a/src/App.tsx b/src/App.tsx
index 8361dfe..dbc5a36 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -18,7 +18,7 @@ const SourceEditor = lazy(() => import('./components/SourceEditor'))
 import { offsetInMarkdown, type CursorAnchor } from './editor/cursorSync'
 import { insertPlainText, insertLinkText } from './editor/paste'
 import { isImeComposing } from './utils/ime'
-import { ConfirmSaveModal, AboutModal, ShortcutsModal, LinkModal, ErrorModal } from './components/Modals'
+import { ConfirmSaveModal, AboutModal, ShortcutsModal, LinkModal, ErrorModal , EncodingConvertModal } from './components/Modals'
 import { tabsReducer, createTab, activeTab, isDirty, type DocTab, type TabsState } from './stores/tabs'
 import { countWords, countChars, extractOutline, baseName, isPathInside, type OutlineItem } from './utils/text'
 import { callUndo, callRedo, focusEditor, type CursorInfo } from './editor/editor'
@@ -472,11 +472,32 @@ export default function App() {
 
   const handleSidebarOpenFolder = useCallback(() => { void openFolder() }, [openFolder])
 
-  const saveTab = useCallback(async (target: DocTab, saveAs: boolean): Promise<boolean> => {
+  // 非 UTF-8 文档保存转码提示（docs/29 D1，用户拍板加）：按路径记已确认，
+  // 本次运行内同一文件只提示一次；确认后走 finishSave 完成落盘收尾。
+  const encodingAckedRef = useRef<Set<string>>(new Set())
+  const [encodingPrompt, setEncodingPrompt] = useState<{ target: DocTab; path: string; snapshot: string } | null>(null)
+
+  /** 保存落盘后的收尾：标已保存（编码如实记为 UTF-8）、刷树、更新基线、清恢复记录。 */
+  const finishSave = useCallback(async (target: DocTab, path: string, snapshot: string) => {
+    const oldKey = recoveryKey(target)
+    dispatch({ type: 'saved', id: target.id, savedContent: snapshot, path, title: baseName(path), encoding: 'UTF-8' })
+    // 落点变化（未命名首次保存、另存为）意味着磁盘上多/改了一个文件，刷新左侧文件树
+    if (target.path !== path) setTreeRefresh((n) => n + 1)
+    const stat = await statFile(path)
+    if (stat.exists) baselinesRef.current.set(target.id, { mtimeMs: stat.mtimeMs, size: stat.size })
+    // 恢复记录可能按旧键（未命名/旧路径）写入，新旧键都清，避免下次启动误报草稿
+    const newKey = recoveryKey({ id: target.id, path })
+    for (const key of new Set([oldKey, newKey])) {
+      recoveryWrittenRef.current.delete(key)
+      void store.deleteRecovery(key)
+    }
+    pushRecent(path)
+  }, [pushRecent])
+
+  const saveTab = useCallback(async (target: DocTab, saveAs: boolean, fromAutosave = false): Promise<boolean> => {
     // 审计修复：保存用调用时刻的快照；saved 只把这份快照标为已保存，
     // 写盘期间新输入的内容保持「脏」，不会被误标、不会丢恢复记录。
     const snapshot = target.content
-    const oldKey = recoveryKey(target)
     try {
       if (!tauriMode) {
         downloadTextFile(`${target.title}.md`, snapshot)
@@ -498,25 +519,35 @@ export default function App() {
         path = await pickSaveFile(path ?? (workspaceRoot ? joinPath(workspaceRoot, `${target.title}.md`) : `${target.title}.md`))
         if (!path) return false
       }
-      await writeTextFile(path, toDiskContent(snapshot, target.lineEnding), target.hadBom)
-      dispatch({ type: 'saved', id: target.id, savedContent: snapshot, path, title: baseName(path) })
-      // 落点变化（未命名首次保存、另存为）意味着磁盘上多/改了一个文件，刷新左侧文件树
-      if (target.path !== path) setTreeRefresh((n) => n + 1)
-      const stat = await statFile(path)
-      if (stat.exists) baselinesRef.current.set(target.id, { mtimeMs: stat.mtimeMs, size: stat.size })
-      // 恢复记录可能按旧键（未命名/旧路径）写入，新旧键都清，避免下次启动误报草稿
-      const newKey = recoveryKey({ id: target.id, path })
-      for (const key of new Set([oldKey, newKey])) {
-        recoveryWrittenRef.current.delete(key)
-        void store.deleteRecovery(key)
+      // 非 UTF-8 文档保存会转码为 UTF-8：首次保存前提示一次（按路径记已确认）。
+      // 自动保存不弹窗、也不静默转码——跳过本轮，等手动保存/关窗保存时提示。
+      if (target.encoding !== 'UTF-8' && !encodingAckedRef.current.has(path)) {
+        if (fromAutosave) return false
+        setEncodingPrompt({ target, path, snapshot })
+        return false
       }
-      pushRecent(path)
+      await writeTextFile(path, toDiskContent(snapshot, target.lineEnding), target.hadBom)
+      await finishSave(target, path, snapshot)
       return true
     } catch (e) {
       setError(String(e))
       return false
     }
-  }, [tauriMode, pushRecent, workspaceRoot])
+  }, [tauriMode, finishSave, workspaceRoot])
+
+  /** 编码提示确认：记下该路径已确认，用弹窗时冻结的快照完成落盘。 */
+  const confirmEncodingSave = useCallback(async () => {
+    const job = encodingPrompt
+    if (!job) return
+    setEncodingPrompt(null)
+    encodingAckedRef.current.add(job.path)
+    try {
+      await writeTextFile(job.path, toDiskContent(job.snapshot, job.target.lineEnding), job.target.hadBom)
+      await finishSave(job.target, job.path, job.snapshot)
+    } catch (e) {
+      setError(String(e))
+    }
+  }, [encodingPrompt, finishSave])
 
   const requestClose = useCallback((ids: string[], after: () => void) => {
     const dirtyOnes = state.tabs.filter((t) => ids.includes(t.id) && isDirty(t))
@@ -731,7 +762,7 @@ export default function App() {
     const timer = window.setInterval(() => {
       for (const t of stateRef.current.tabs) {
         // 冲突弹窗正等用户裁决的标签不自动保存，否则会抢先覆盖外部修改
-        if (t.path && isDirty(t) && conflictRef.current !== t.id) void saveTabRef.current(t, false)
+        if (t.path && isDirty(t) && conflictRef.current !== t.id) void saveTabRef.current(t, false, true)
       }
     }, Math.max(10, ui.autosaveSeconds) * 1000)
     return () => window.clearInterval(timer)
@@ -1363,7 +1394,7 @@ export default function App() {
   }, [tauriMode, flash])
 
   anyModalRef.current = Boolean(
-    modal || appearanceOpen || exportOpen || pendingClose || conflict
+    modal || appearanceOpen || exportOpen || pendingClose || conflict || encodingPrompt
     || promptSpec || confirmSpec || quitOpen || gitSettingsOpen || (recoveryOffer.length > 0 && !recoveryDismissed),
   )
   findOpenRef.current = findUi.open
@@ -1857,6 +1888,15 @@ export default function App() {
         />
       )}
       {error && <ErrorModal message={error} onClose={() => setError(null)} />}
+      {encodingPrompt && (
+        <EncodingConvertModal
+          encoding={encodingPrompt.target.encoding}
+          fileName={baseName(encodingPrompt.path)}
+          onConfirm={() => { void confirmEncodingSave() }}
+          onCancel={() => setEncodingPrompt(null)}
+        />
+      )}
+
     </div>
   )
 }
diff --git a/src/components/Modals.tsx b/src/components/Modals.tsx
index 8bda8e1..c537a0e 100644
--- a/src/components/Modals.tsx
+++ b/src/components/Modals.tsx
@@ -28,6 +28,24 @@ export function ConfirmSaveModal({ title, onSave, onDiscard, onCancel }: {
   )
 }
 
+export function EncodingConvertModal({ encoding, fileName, onConfirm, onCancel }: {
+  encoding: string
+  fileName: string
+  onConfirm: () => void
+  onCancel: () => void
+}) {
+  return (
+    <Shell onCancel={onCancel}>
+      <h3>文档编码将转为 UTF-8</h3>
+      <p>「{fileName}」原是 {encoding} 编码。本编辑器统一以 UTF-8 保存，保存后文件编码将转为 UTF-8（内容不变）。本次运行内，同一文件只提示这一次。</p>
+      <div className="modal-actions">
+        <button onClick={onCancel}>取消保存</button>
+        <button className="primary" onClick={onConfirm}>转为 UTF-8 保存</button>
+      </div>
+    </Shell>
+  )
+}
+
 export function AboutModal({ onClose }: { onClose: () => void }) {
   return (
     <Shell onCancel={onClose}>
diff --git a/src/stores/tabs.ts b/src/stores/tabs.ts
index 04050d3..f39667a 100644
--- a/src/stores/tabs.ts
+++ b/src/stores/tabs.ts
@@ -46,7 +46,7 @@ export type TabsAction =
   | { type: 'open'; tab: DocTab }
   | { type: 'activate'; id: string }
   | { type: 'updateContent'; id: string; content: string }
-  | { type: 'saved'; id: string; savedContent: string; path?: string; title?: string }
+  | { type: 'saved'; id: string; savedContent: string; path?: string; title?: string; encoding?: string }
   | { type: 'syncEditorContent'; id: string; content: string }
   | { type: 'loadContent'; id: string; content: string; encoding?: string; lineEnding?: string; hadBom?: boolean }
   | { type: 'setPath'; id: string; path: string; title: string }
@@ -93,7 +93,7 @@ export function tabsReducer(state: TabsState, action: TabsAction): TabsState {
         ...state,
         tabs: state.tabs.map((t) =>
           t.id === action.id
-            ? { ...t, savedContent: action.savedContent, path: action.path ?? t.path, title: action.title ?? t.title }
+            ? { ...t, savedContent: action.savedContent, path: action.path ?? t.path, title: action.title ?? t.title, encoding: action.encoding ?? t.encoding }
             : t,
         ),
       }
diff --git a/tests/encoding-modal.test.tsx b/tests/encoding-modal.test.tsx
new file mode 100644
index 0000000..66cfa7a
--- /dev/null
+++ b/tests/encoding-modal.test.tsx
@@ -0,0 +1,27 @@
+// docs/29 D1：非 UTF-8 文档保存转码提示弹窗的渲染与回调契约。
+import { describe, it, expect, vi } from 'vitest'
+import { createRoot } from 'react-dom/client'
+import { act } from 'react-dom/test-utils'
+import { EncodingConvertModal } from '../src/components/Modals'
+
+describe('EncodingConvertModal', () => {
+  it('显示原编码与文件名，确认/取消回调正确', async () => {
+    const container = document.createElement('div')
+    document.body.appendChild(container)
+    const root = createRoot(container)
+    const onConfirm = vi.fn()
+    const onCancel = vi.fn()
+    await act(async () => {
+      root.render(<EncodingConvertModal encoding="GBK" fileName="老文档.md" onConfirm={onConfirm} onCancel={onCancel} />)
+    })
+    expect(container.textContent).toContain('GBK')
+    expect(container.textContent).toContain('老文档.md')
+    expect(container.textContent).toContain('转为 UTF-8')
+    const buttons = [...container.querySelectorAll('button')]
+    buttons.find((b) => b.textContent?.includes('转为 UTF-8'))?.click()
+    expect(onConfirm).toHaveBeenCalledTimes(1)
+    buttons.find((b) => b.textContent?.includes('取消'))?.click()
+    expect(onCancel).toHaveBeenCalledTimes(1)
+    await act(async () => { root.unmount() })
+  })
+})