diff --git a/README.md b/README.md
index 260ab8e..3222f8f 100644
--- a/README.md
+++ b/README.md
@@ -30,8 +30,8 @@ yarn add @xuqm/rn-common @xuqm/rn-im @xuqm/rn-push @xuqm/rn-update
 
 ## 入口
 
-- `XuqmSDK.initialize({ appKey, debug })`
-- `XuqmSDK.login({ userId, userSig, profile, expiresAt, refreshUserSig })`
+- `XuqmSDK.initialize({ appKey, logLevel })`
+- `XuqmSDK.login({ userId, userSig })`
 - `XuqmSDK.logout()`
 - `ImSDK`
 - `PushSDK`
diff --git a/packages/im/src/ImSDK.ts b/packages/im/src/ImSDK.ts
index 80caf9d..cefae04 100644
--- a/packages/im/src/ImSDK.ts
+++ b/packages/im/src/ImSDK.ts
@@ -283,33 +283,18 @@ function resolveMimeTypeFromUri(uri: string, fallback: string): string {
 
 export const ImSDK = {
   /**
-   * Login to IM service. Fetches a token internally and opens the WebSocket connection.
-   * Pass dbName to enable local SQLite message caching (requires @nozbe/watermelondb).
+   * Login to IM service with a pre-obtained userSig and open the WebSocket connection.
    */
-  async login(userId: string, dbName?: string): Promise<void> {
+  async login(userId: string, userSig: string): Promise<void> {
     const config = getConfig()
-    const device = await getDeviceInfo()
     client?.disconnect()
-    const res = await apiRequest<{ token: string }>('/api/im/auth/login', {
-      method: 'POST',
-      skipAuth: true,
-      params: {
-        appId: config.appId,
-        userId,
-        deviceId: device.deviceId,
-        platform: device.platform,
-        brand: device.brand,
-        model: device.model,
-        osVersion: device.osVersion,
-      },
-    })
-    await _saveToken(res.token)
+    await _saveToken(userSig)
     _currentUserId = userId
     setCommonUserId(userId)
 
-    ImDatabase.init(dbName ?? buildDbName(config.appKey, userId))
+    ImDatabase.init(buildDbName(config.appKey, userId))
 
-    client = new ImClient(config.imWsUrl, res.token, config.appId)
+    client = new ImClient(config.imWsUrl, userSig, config.appId)
     client.addListener({
       onConnected: () => {
         _syncHistoryForAllConversations().catch(() => {})
@@ -318,32 +303,6 @@ export const ImSDK = {
     void client.connect()
   },
 
-  /**
-   * Login with a pre-obtained IM token (e.g. from demo-service).
-   * Sets up the IM connection without calling the auth endpoint.
-   */
-  async loginWithToken(userId: string, token: string, dbName?: string): Promise<void> {
-    const config = getConfig()
-    client?.disconnect()
-    await _saveToken(token)
-    _currentUserId = userId
-    setCommonUserId(userId)
-
-    ImDatabase.init(dbName ?? buildDbName(config.appKey, userId))
-
-    client = new ImClient(config.imWsUrl, token, config.appId)
-    client.addListener({
-      onConnected: () => {
-        _syncHistoryForAllConversations().catch(() => {})
-      },
-    })
-    void client.connect()
-  },
-
-  async loginWithUserSig(userId: string, userSig: string, dbName?: string): Promise<void> {
-    return ImSDK.loginWithToken(userId, userSig, dbName)
-  },
-
   async reconnect(): Promise<void> {
     const config = getConfig()
     const token = await _getToken()
diff --git a/packages/im/src/upload.ts b/packages/im/src/upload.ts
index f59a85c..8160644 100644
--- a/packages/im/src/upload.ts
+++ b/packages/im/src/upload.ts
@@ -24,7 +24,7 @@ export async function uploadFile(
   const config = getConfig()
   const token = await _getToken()
   if (!token) {
-    throw new Error('[uploadFile] No active session — call ImSDK.loginWithToken() first.')
+    throw new Error('[uploadFile] No active session — call XuqmSDK.login() first.')
   }
 
   const form = new FormData()
diff --git a/src/sdk.ts b/src/sdk.ts
index dad5230..b341d07 100644
--- a/src/sdk.ts
+++ b/src/sdk.ts
@@ -12,7 +12,7 @@ let currentSession: UnifiedLoginOptions | null = null
 async function applyLoginSession(session: UnifiedLoginOptions): Promise<void> {
   setCommonUserId(session.userId)
   try {
-    await ImSDK.loginWithUserSig(session.userId, session.userSig)
+    await ImSDK.login(session.userId, session.userSig)
   } catch (error) {
     setCommonUserId(null)
     currentSession = null