diff --git a/apps/application/chat_pipeline/step/chat_step/impl/base_chat_step.py b/apps/application/chat_pipeline/step/chat_step/impl/base_chat_step.py
index cd17d4a10..adc11f6b4 100644
--- a/apps/application/chat_pipeline/step/chat_step/impl/base_chat_step.py
+++ b/apps/application/chat_pipeline/step/chat_step/impl/base_chat_step.py
@@ -416,10 +416,10 @@ class BaseChatStep(IChatStep):
             reasoning_result_end = reasoning.get_end_reasoning_content()
             content = reasoning_result.get('content') + reasoning_result_end.get('content')
             if 'reasoning_content' in chat_result.response_metadata:
-                reasoning_content = chat_result.response_metadata.get('reasoning_content', '')
+                reasoning_content = (chat_result.response_metadata.get('reasoning_content', '') or '')
             else:
-                reasoning_content = reasoning_result.get('reasoning_content') + reasoning_result_end.get(
-                    'reasoning_content')
+                reasoning_content = (reasoning_result.get('reasoning_content') or "") + (reasoning_result_end.get(
+                    'reasoning_content') or "")
             post_response_handler.handler(chat_id, chat_record_id, paragraph_list, problem_text,
                                           content, manage, self, padding_problem_text,
                                           reasoning_content=reasoning_content)
diff --git a/apps/application/flow/step_node/ai_chat_step_node/impl/base_chat_node.py b/apps/application/flow/step_node/ai_chat_step_node/impl/base_chat_node.py
index 20dc22b25..25151347e 100644
--- a/apps/application/flow/step_node/ai_chat_step_node/impl/base_chat_node.py
+++ b/apps/application/flow/step_node/ai_chat_step_node/impl/base_chat_node.py
@@ -108,9 +108,9 @@ def write_context(node_variable: Dict, workflow_variable: Dict, node: INode, wor
     content = reasoning_result.get('content') + reasoning_result_end.get('content')
     meta = {**response.response_metadata, **response.additional_kwargs}
     if 'reasoning_content' in meta:
-        reasoning_content = meta.get('reasoning_content', '')
+        reasoning_content = (meta.get('reasoning_content', '') or '')
     else:
-        reasoning_content = reasoning_result.get('reasoning_content') + reasoning_result_end.get('reasoning_content')
+        reasoning_content = (reasoning_result.get('reasoning_content') or '') + (reasoning_result_end.get('reasoning_content') or '')
     _write_context(node_variable, workflow_variable, node, workflow, content, reasoning_content)