diff --git a/packages/dbgpt-app/src/dbgpt_app/openapi/api_v1/agentic_data_api.py b/packages/dbgpt-app/src/dbgpt_app/openapi/api_v1/agentic_data_api.py
index bcabffb149..3b54c26107 100644
--- a/packages/dbgpt-app/src/dbgpt_app/openapi/api_v1/agentic_data_api.py
+++ b/packages/dbgpt-app/src/dbgpt_app/openapi/api_v1/agentic_data_api.py
@@ -26,6 +26,7 @@
 from dbgpt_app.openapi.api_view_model import (
     ConversationVo,
     Result,
+    resolve_dialogue_user_name,
 )
 from dbgpt_serve.datasource.manages import ConnectorManager
 from dbgpt_serve.utils.auth import UserRequest, get_user_from_headers
@@ -4069,7 +4070,9 @@ async def chat_react_agent(
         dialogue.select_param,
         dialogue.model_name,
     )
-    dialogue.user_name = user_token.user_id if user_token else dialogue.user_name
+    dialogue.user_name = resolve_dialogue_user_name(
+        dialogue.user_name, user_token.user_id if user_token else None
+    )
     headers = {
         "Content-Type": "text/event-stream",
         "Cache-Control": "no-cache",
diff --git a/packages/dbgpt-app/src/dbgpt_app/openapi/api_v1/api_v1.py b/packages/dbgpt-app/src/dbgpt_app/openapi/api_v1/api_v1.py
index 84008cd2a3..751edc9f57 100644
--- a/packages/dbgpt-app/src/dbgpt_app/openapi/api_v1/api_v1.py
+++ b/packages/dbgpt-app/src/dbgpt_app/openapi/api_v1/api_v1.py
@@ -44,6 +44,7 @@
     ConversationVo,
     MessageVo,
     Result,
+    resolve_dialogue_user_name,
 )
 from dbgpt_app.scene import BaseChat, ChatFactory, ChatParam, ChatScene
 from dbgpt_serve.agent.db.gpts_app import UserRecentAppsDao, adapt_native_app_model
@@ -512,7 +513,9 @@ async def chat_prepare(
 ):
     logger.info(json.dumps(dialogue.__dict__))
     # dialogue.model_name = CFG.LLM_MODEL
-    dialogue.user_name = user_token.user_id if user_token else dialogue.user_name
+    dialogue.user_name = resolve_dialogue_user_name(
+        dialogue.user_name, user_token.user_id if user_token else None
+    )
     logger.info(f"chat_prepare:{dialogue}")
     ## check conv_uid
     chat: BaseChat = await get_chat_instance(dialogue)
@@ -520,7 +523,7 @@ async def chat_prepare(
     await chat.prepare()
 
     # Refresh messages
-    return Result.succ(get_hist_messages(dialogue.conv_uid, user_token.user_id))
+    return Result.succ(get_hist_messages(dialogue.conv_uid, dialogue.user_name))
 
 
 @router.post("/v1/chat/completions")
@@ -533,7 +536,9 @@ async def chat_completions(
         f"chat_completions:{dialogue.chat_mode},{dialogue.select_param},"
         f"{dialogue.model_name}, timestamp={int(time.time() * 1000)}"
     )
-    dialogue.user_name = user_token.user_id if user_token else dialogue.user_name
+    dialogue.user_name = resolve_dialogue_user_name(
+        dialogue.user_name, user_token.user_id if user_token else None
+    )
     dialogue = adapt_native_app_model(dialogue)
 
     # Handle knowledge space selection from ext_info for normal chat mode
diff --git a/packages/dbgpt-app/src/dbgpt_app/openapi/api_view_model.py b/packages/dbgpt-app/src/dbgpt_app/openapi/api_view_model.py
index 5eac2b9d75..7a1a5ecae1 100644
--- a/packages/dbgpt-app/src/dbgpt_app/openapi/api_view_model.py
+++ b/packages/dbgpt-app/src/dbgpt_app/openapi/api_view_model.py
@@ -10,6 +10,13 @@
 T = TypeVar("T")
 
 
+def resolve_dialogue_user_name(
+    request_user_name: Optional[str], token_user_id: Optional[str]
+) -> Optional[str]:
+    """Prefer explicit dialogue user_name and fall back to the auth token user."""
+    return request_user_name or token_user_id
+
+
 class Result(BaseModel, Generic[T]):
     success: bool
     err_code: Optional[str] = None
diff --git a/packages/dbgpt-app/src/dbgpt_app/tests/test_chat_completions_user_name.py b/packages/dbgpt-app/src/dbgpt_app/tests/test_chat_completions_user_name.py
new file mode 100644
index 0000000000..e5cd0997f2
--- /dev/null
+++ b/packages/dbgpt-app/src/dbgpt_app/tests/test_chat_completions_user_name.py
@@ -0,0 +1,48 @@
+import pytest
+
+from dbgpt_app.openapi.api_view_model import resolve_dialogue_user_name
+from dbgpt_serve.utils.auth import UserRequest
+
+
+def test_resolve_dialogue_user_name_preserves_explicit_request_user():
+    assert resolve_dialogue_user_name("request_user", "token_user") == "request_user"
+
+
+def test_resolve_dialogue_user_name_falls_back_to_authenticated_user():
+    assert resolve_dialogue_user_name(None, "token_user") == "token_user"
+
+
+@pytest.mark.asyncio
+async def test_chat_prepare_refreshes_history_with_resolved_dialogue_user(monkeypatch):
+    from dbgpt_app.openapi.api_v1 import api_v1
+    from dbgpt_app.openapi.api_view_model import ConversationVo
+
+    class FakeChat:
+        async def prepare(self):
+            return None
+
+    captured = {}
+
+    async def fake_get_chat_instance(dialogue):
+        captured["chat_user_name"] = dialogue.user_name
+        return FakeChat()
+
+    def fake_get_hist_messages(conv_uid, user_name=None):
+        captured["history_conv_uid"] = conv_uid
+        captured["history_user_name"] = user_name
+        return ["history"]
+
+    monkeypatch.setattr(api_v1, "get_chat_instance", fake_get_chat_instance)
+    monkeypatch.setattr(api_v1, "get_hist_messages", fake_get_hist_messages)
+
+    result = await api_v1.chat_prepare(
+        ConversationVo(conv_uid="conv-1", user_name="request_user"),
+        UserRequest(user_id="token_user"),
+    )
+
+    assert result.data == ["history"]
+    assert captured == {
+        "chat_user_name": "request_user",
+        "history_conv_uid": "conv-1",
+        "history_user_name": "request_user",
+    }
diff --git a/packages/dbgpt-serve/src/dbgpt_serve/conversation/models/models.py b/packages/dbgpt-serve/src/dbgpt_serve/conversation/models/models.py
index acfaa110ed..eb8cca689b 100644
--- a/packages/dbgpt-serve/src/dbgpt_serve/conversation/models/models.py
+++ b/packages/dbgpt-serve/src/dbgpt_serve/conversation/models/models.py
@@ -76,7 +76,7 @@ def to_response(self, entity: ServeEntity) -> ServerResponse:
             conv_uid=entity.conv_uid,
             user_input=entity.summary,
             chat_mode=entity.chat_mode,
-            user_name="",
+            user_name=entity.user_name,
             sys_code=entity.sys_code,
             gmt_created=gmt_created,
             gmt_modified=gmt_modified,
diff --git a/packages/dbgpt-serve/src/dbgpt_serve/conversation/tests/test_models.py b/packages/dbgpt-serve/src/dbgpt_serve/conversation/tests/test_models.py
index 7f0aa17959..e5ed0fed37 100644
--- a/packages/dbgpt-serve/src/dbgpt_serve/conversation/tests/test_models.py
+++ b/packages/dbgpt-serve/src/dbgpt_serve/conversation/tests/test_models.py
@@ -46,6 +46,21 @@ def test_entity_create(default_entity_dict):
         session.add(entity)
 
 
+def test_to_response_preserves_user_name(dao):
+    entity = ServeEntity(
+        conv_uid="test_conv_uid",
+        summary="hello",
+        chat_mode="chat_normal",
+        user_name="request_user",
+        sys_code="dbgpt",
+        app_code="chat_normal",
+    )
+
+    response = dao.to_response(entity)
+
+    assert response.user_name == "request_user"
+
+
 def test_entity_unique_key(default_entity_dict):
     # TODO: implement your test case
     pass