diff --git a/swift/llm/deploy.py b/swift/llm/deploy.py
index 438c87a3a8..0baa80f6a7 100644
--- a/swift/llm/deploy.py
+++ b/swift/llm/deploy.py
@@ -426,7 +426,7 @@ async def _generate_stream():
         yield 'data: [DONE]\n\n'
 
     if request.stream:
-        return StreamingResponse(_generate_stream())
+        return StreamingResponse(_generate_stream(), media_type='text/event-stream')
     else:
         return await _generate_full()
 
@@ -605,7 +605,7 @@ async def _generate_stream():
             yield 'data: [DONE]\n\n'
 
     if request.stream:
-        return StreamingResponse(_generate_stream())
+        return StreamingResponse(_generate_stream(), media_type='text/event-stream')
     else:
         return await _generate_full()
 
@@ -833,7 +833,7 @@ def _generate_stream():
         yield 'data: [DONE]\n\n'
 
     if request.stream:
-        return StreamingResponse(_generate_stream())
+        return StreamingResponse(_generate_stream(), media_type='text/event-stream')
     else:
         return await _generate_full()