diff --git a/src/renderer/src/pages/settings/DataSettings/S3Settings.tsx b/src/renderer/src/pages/settings/DataSettings/S3Settings.tsx
index 9ea3dbceac..ccf8b41ae9 100644
--- a/src/renderer/src/pages/settings/DataSettings/S3Settings.tsx
+++ b/src/renderer/src/pages/settings/DataSettings/S3Settings.tsx
@@ -30,7 +30,9 @@ const S3Settings: FC = () => {
     root: s3RootInit = '',
     syncInterval: s3SyncIntervalInit = 0,
     maxBackups: s3MaxBackupsInit = 5,
-    skipBackupFile: s3SkipBackupFileInit = false
+    skipBackupFile: s3SkipBackupFileInit = false,
+    singleFileOverwrite: s3SingleFileOverwriteInit = false,
+    singleFileName: s3SingleFileNameInit = ''
   } = s3
 
   const [endpoint, setEndpoint] = useState<string | undefined>(s3EndpointInit)
@@ -40,6 +42,8 @@ const S3Settings: FC = () => {
   const [secretAccessKey, setSecretAccessKey] = useState<string | undefined>(s3SecretAccessKeyInit)
   const [root, setRoot] = useState<string | undefined>(s3RootInit)
   const [skipBackupFile, setSkipBackupFile] = useState<boolean>(s3SkipBackupFileInit)
+  const [singleFileOverwrite, setSingleFileOverwrite] = useState<boolean>(!!s3SingleFileOverwriteInit)
+  const [singleFileName, setSingleFileName] = useState<string | undefined>(s3SingleFileNameInit)
   const [backupManagerVisible, setBackupManagerVisible] = useState(false)
 
   const [syncInterval, setSyncInterval] = useState<number>(s3SyncIntervalInit)
@@ -81,6 +85,15 @@ const S3Settings: FC = () => {
     dispatch(setS3Partial({ skipBackupFile: value }))
   }
 
+  const onSingleFileOverwriteChange = (value: boolean) => {
+    setSingleFileOverwrite(value)
+    dispatch(setS3Partial({ singleFileOverwrite: value }))
+  }
+
+  const onSingleFileNameBlur = () => {
+    dispatch(setS3Partial({ singleFileName: singleFileName || '' }))
+  }
+
   const renderSyncStatus = () => {
     if (!endpoint) return null
 
diff --git a/src/renderer/src/services/BackupService.ts b/src/renderer/src/services/BackupService.ts
index c168bd489b..57f2f8e8d0 100644
--- a/src/renderer/src/services/BackupService.ts
+++ b/src/renderer/src/services/BackupService.ts
@@ -168,7 +168,9 @@ export async function backupToWebdav({
     webdavPath,
     webdavMaxBackups,
     webdavSkipBackupFile,
-    webdavDisableStream
+    webdavDisableStream,
+    webdavSingleFileOverwrite,
+    webdavSingleFileName
   } = store.getState().settings
   let deviceType = 'unknown'
   let hostname = 'unknown'
@@ -179,7 +181,12 @@ export async function backupToWebdav({
     logger.error('Failed to get device type or hostname:', error as Error)
   }
   const timestamp = dayjs().format('YYYYMMDDHHmmss')
-  const backupFileName = customFileName || `cherry-studio.${timestamp}.${hostname}.${deviceType}.zip`
+  let backupFileName = customFileName || `cherry-studio.${timestamp}.${hostname}.${deviceType}.zip`
+  // 覆盖式单文件备份（仅在自动备份流程且保留份数=1时生效）
+  if (autoBackupProcess && webdavMaxBackups === 1 && webdavSingleFileOverwrite) {
+    const base = (webdavSingleFileName || `cherry-studio.${hostname}.${deviceType}`).trim()
+    backupFileName = base.endsWith('.zip') ? base : `${base}.zip`
+  }
   const finalFileName = backupFileName.endsWith('.zip') ? backupFileName : `${backupFileName}.zip`
   const backupData = await getBackupData()
 
@@ -212,8 +219,8 @@ export async function backupToWebdav({
       })
       showMessage && window.toast.success(i18n.t('message.backup.success'))
 
-      // 清理旧备份文件
-      if (webdavMaxBackups > 0) {
+      // 覆盖式单文件备份启用时（且=1），不进行清理
+      if (webdavMaxBackups > 0 && !(autoBackupProcess && webdavMaxBackups === 1 && webdavSingleFileOverwrite)) {
         try {
           // 获取所有备份文件
           const files = await window.api.backup.listWebdavFiles({
@@ -353,7 +360,12 @@ export async function backupToS3({
     logger.error('Failed to get device type or hostname:', error as Error)
   }
   const timestamp = dayjs().format('YYYYMMDDHHmmss')
-  const backupFileName = customFileName || `cherry-studio.${timestamp}.${hostname}.${deviceType}.zip`
+  let backupFileName = customFileName || `cherry-studio.${timestamp}.${hostname}.${deviceType}.zip`
+  // 覆盖式单文件备份（仅在自动备份流程且保留份数=1时生效）
+  if (autoBackupProcess && s3Config.maxBackups === 1 && s3Config.singleFileOverwrite) {
+    const base = (s3Config.singleFileName || `cherry-studio.${hostname}.${deviceType}`).trim()
+    backupFileName = base.endsWith('.zip') ? base : `${base}.zip`
+  }
   const finalFileName = backupFileName.endsWith('.zip') ? backupFileName : `${backupFileName}.zip`
   const backupData = await getBackupData()
 
diff --git a/src/renderer/src/store/settings.ts b/src/renderer/src/store/settings.ts
index 273653aa0c..93ab203d14 100644
--- a/src/renderer/src/store/settings.ts
+++ b/src/renderer/src/store/settings.ts
@@ -119,6 +119,9 @@ export interface SettingsState {
   webdavMaxBackups: number
   webdavSkipBackupFile: boolean
   webdavDisableStream: boolean
+  // 覆盖式单文件备份（WebDAV）
+  webdavSingleFileOverwrite?: boolean
+  webdavSingleFileName?: string
   translateModelPrompt: string
   autoTranslateWithSpace: boolean
   showTranslateConfirm: boolean
@@ -210,6 +213,9 @@ export interface SettingsState {
   localBackupSyncInterval: number
   localBackupMaxBackups: number
   localBackupSkipBackupFile: boolean
+  // 覆盖式单文件备份（Local）
+  localSingleFileOverwrite?: boolean
+  localSingleFileName?: string
   defaultPaintingProvider: PaintingProvider
   s3: S3Config
   // Developer mode
@@ -306,6 +312,8 @@ export const initialState: SettingsState = {
   webdavMaxBackups: 0,
   webdavSkipBackupFile: false,
   webdavDisableStream: false,
+  webdavSingleFileOverwrite: false,
+  webdavSingleFileName: '',
   translateModelPrompt: TRANSLATE_PROMPT,
   autoTranslateWithSpace: false,
   showTranslateConfirm: true,
@@ -389,6 +397,8 @@ export const initialState: SettingsState = {
   localBackupSyncInterval: 0,
   localBackupMaxBackups: 0,
   localBackupSkipBackupFile: false,
+  localSingleFileOverwrite: false,
+  localSingleFileName: '',
   defaultPaintingProvider: 'zhipu',
   s3: {
     endpoint: '',
@@ -400,7 +410,9 @@ export const initialState: SettingsState = {
     autoSync: false,
     syncInterval: 0,
     maxBackups: 0,
-    skipBackupFile: false
+    skipBackupFile: false,
+    singleFileOverwrite: false,
+    singleFileName: ''
   },
 
   // Developer mode
@@ -556,6 +568,12 @@ const settingsSlice = createSlice({
     setWebdavDisableStream: (state, action: PayloadAction<boolean>) => {
       state.webdavDisableStream = action.payload
     },
+    setWebdavSingleFileOverwrite: (state, action: PayloadAction<boolean>) => {
+      state.webdavSingleFileOverwrite = action.payload
+    },
+    setWebdavSingleFileName: (state, action: PayloadAction<string>) => {
+      state.webdavSingleFileName = action.payload
+    },
     setCodeExecution: (state, action: PayloadAction<{ enabled?: boolean; timeoutMinutes?: number }>) => {
       if (action.payload.enabled !== undefined) {
         state.codeExecution.enabled = action.payload.enabled
@@ -816,6 +834,12 @@ const settingsSlice = createSlice({
     setLocalBackupSkipBackupFile: (state, action: PayloadAction<boolean>) => {
       state.localBackupSkipBackupFile = action.payload
     },
+    setLocalSingleFileOverwrite: (state, action: PayloadAction<boolean>) => {
+      state.localSingleFileOverwrite = action.payload
+    },
+    setLocalSingleFileName: (state, action: PayloadAction<string>) => {
+      state.localSingleFileName = action.payload
+    },
     setDefaultPaintingProvider: (state, action: PayloadAction<PaintingProvider>) => {
       state.defaultPaintingProvider = action.payload
     },
@@ -903,6 +927,8 @@ export const {
   setWebdavMaxBackups,
   setWebdavSkipBackupFile,
   setWebdavDisableStream,
+  setWebdavSingleFileOverwrite,
+  setWebdavSingleFileName,
   setCodeExecution,
   setCodeEditor,
   setCodeViewer,
@@ -974,6 +1000,8 @@ export const {
   setLocalBackupSyncInterval,
   setLocalBackupMaxBackups,
   setLocalBackupSkipBackupFile,
+  setLocalSingleFileOverwrite,
+  setLocalSingleFileName,
   setDefaultPaintingProvider,
   setS3,
   setS3Partial,
diff --git a/src/renderer/src/types/index.ts b/src/renderer/src/types/index.ts
index 1b1d69c3cb..6ae0579d13 100644
--- a/src/renderer/src/types/index.ts
+++ b/src/renderer/src/types/index.ts
@@ -873,6 +873,10 @@ export type S3Config = {
   autoSync: boolean
   syncInterval: number
   maxBackups: number
+  /** 当自动备份且保留份数=1时，是否启用覆盖式单文件备份 */
+  singleFileOverwrite?: boolean
+  /** 覆盖式单文件备份的自定义文件名（可选，默认使用不带时间戳的设备名+主机名） */
+  singleFileName?: string
 }
 
 export type { Message } from './newMessage'