diff --git a/astrbot/core/db/__init__.py b/astrbot/core/db/__init__.py
index 087aa625bd..4c4f8ab58d 100644
--- a/astrbot/core/db/__init__.py
+++ b/astrbot/core/db/__init__.py
@@ -722,6 +722,13 @@ async def delete_platform_session(self, session_id: str) -> None:
         """Delete a Platform session by its ID."""
         ...
 
+    @abc.abstractmethod
+    async def migrate_user_webchat_data(
+        self, old_username: str, new_username: str
+    ) -> None:
+        """Migrate all webchat user data when username is changed."""
+        ...
+
     # ====
     # ChatUI Project Management
     # ====
diff --git a/astrbot/core/db/sqlite.py b/astrbot/core/db/sqlite.py
index fd6668c0c7..e745b9579e 100644
--- a/astrbot/core/db/sqlite.py
+++ b/astrbot/core/db/sqlite.py
@@ -1616,6 +1616,47 @@ async def delete_platform_session(self, session_id: str) -> None:
                     ),
                 )
 
+    async def migrate_user_webchat_data(
+        self, old_username: str, new_username: str
+    ) -> None:
+        """Migrate all webchat user data when username is changed."""
+        old_fragment = f"!{old_username}!"
+        new_fragment = f"!{new_username}!"
+        async with self.get_db() as session:
+            session: AsyncSession
+            async with session.begin():
+                await session.execute(
+                    update(PlatformSession)
+                    .where(col(PlatformSession.creator) == old_username)
+                    .values(creator=new_username)
+                )
+                await session.execute(
+                    update(ChatUIProject)
+                    .where(col(ChatUIProject.creator) == old_username)
+                    .values(creator=new_username)
+                )
+                await session.execute(
+                    update(ConversationV2)
+                    .where(col(ConversationV2.user_id).like("webchat%"))
+                    .values(
+                        user_id=func.replace(
+                            ConversationV2.user_id, old_fragment, new_fragment
+                        )
+                    )
+                )
+                await session.execute(
+                    update(Preference)
+                    .where(
+                        col(Preference.scope) == "umo",
+                        col(Preference.scope_id).like("webchat%"),
+                    )
+                    .values(
+                        scope_id=func.replace(
+                            Preference.scope_id, old_fragment, new_fragment
+                        )
+                    )
+                )
+
     # ====
     # ChatUI Project Management
     # ====
diff --git a/astrbot/dashboard/routes/auth.py b/astrbot/dashboard/routes/auth.py
index eac5f65b0b..ef7d559492 100644
--- a/astrbot/dashboard/routes/auth.py
+++ b/astrbot/dashboard/routes/auth.py
@@ -6,13 +6,15 @@
 
 from astrbot import logger
 from astrbot.core import DEMO_MODE
+from astrbot.core.db import BaseDatabase
 
 from .route import Response, Route, RouteContext
 
 
 class AuthRoute(Route):
-    def __init__(self, context: RouteContext) -> None:
+    def __init__(self, context: RouteContext, db: BaseDatabase) -> None:
         super().__init__(context)
+        self.db = db
         self.routes = {
             "/auth/login": ("POST", self.login),
             "/auth/account/edit": ("POST", self.edit_account),
@@ -72,9 +74,15 @@ async def edit_account(self):
             if confirm_pwd != new_pwd:
                 return Response().error("两次输入的新密码不一致").__dict__
             self.config["dashboard"]["password"] = new_pwd
+
+        old_username = self.config["dashboard"]["username"]
         if new_username:
             self.config["dashboard"]["username"] = new_username
 
+        # Migrate webchat user data before saving config to keep them in sync.
+        if new_username and new_username != old_username:
+            await self.db.migrate_user_webchat_data(old_username, new_username)
+
         self.config.save_config()
 
         return Response().ok(None, "修改成功").__dict__
diff --git a/astrbot/dashboard/server.py b/astrbot/dashboard/server.py
index cbb7296bd0..2a3f90f479 100644
--- a/astrbot/dashboard/server.py
+++ b/astrbot/dashboard/server.py
@@ -112,7 +112,7 @@ def __init__(
         self.cr = ConfigRoute(self.context, core_lifecycle)
         self.lr = LogRoute(self.context, core_lifecycle.log_broker)
         self.sfr = StaticFileRoute(self.context)
-        self.ar = AuthRoute(self.context)
+        self.ar = AuthRoute(self.context, db)
         self.api_key_route = ApiKeyRoute(self.context, db)
         self.chat_route = ChatRoute(self.context, db, core_lifecycle)
         self.open_api_route = OpenApiRoute(