diff --git a/api/core/model_runtime/model_providers/moonshot/llm/llm.py b/api/core/model_runtime/model_providers/moonshot/llm/llm.py
index 5c955c86d3..90d015942e 100644
--- a/api/core/model_runtime/model_providers/moonshot/llm/llm.py
+++ b/api/core/model_runtime/model_providers/moonshot/llm/llm.py
@@ -252,7 +252,7 @@ class MoonshotLargeLanguageModel(OAIAPICompatLargeLanguageModel):
                 # ignore sse comments
                 if chunk.startswith(":"):
                     continue
-                decoded_chunk = chunk.strip().lstrip("data: ").lstrip()
+                decoded_chunk = chunk.strip().removeprefix("data: ")
                 chunk_json = None
                 try:
                     chunk_json = json.loads(decoded_chunk)
diff --git a/api/core/model_runtime/model_providers/openai_api_compatible/llm/llm.py b/api/core/model_runtime/model_providers/openai_api_compatible/llm/llm.py
index e1342fe985..26c090d30e 100644
--- a/api/core/model_runtime/model_providers/openai_api_compatible/llm/llm.py
+++ b/api/core/model_runtime/model_providers/openai_api_compatible/llm/llm.py
@@ -462,7 +462,7 @@ class OAIAPICompatLargeLanguageModel(_CommonOaiApiCompat, LargeLanguageModel):
                 # ignore sse comments
                 if chunk.startswith(":"):
                     continue
-                decoded_chunk = chunk.strip().lstrip("data: ").lstrip()
+                decoded_chunk = chunk.strip().removeprefix("data: ")
                 if decoded_chunk == "[DONE]":  # Some provider returns "data: [DONE]"
                     continue
 
diff --git a/api/core/model_runtime/model_providers/stepfun/llm/llm.py b/api/core/model_runtime/model_providers/stepfun/llm/llm.py
index 43b91a1aec..686809ff2b 100644
--- a/api/core/model_runtime/model_providers/stepfun/llm/llm.py
+++ b/api/core/model_runtime/model_providers/stepfun/llm/llm.py
@@ -250,7 +250,7 @@ class StepfunLargeLanguageModel(OAIAPICompatLargeLanguageModel):
                 # ignore sse comments
                 if chunk.startswith(":"):
                     continue
-                decoded_chunk = chunk.strip().lstrip("data: ").lstrip()
+                decoded_chunk = chunk.strip().removeprefix("data: ")
                 chunk_json = None
                 try:
                     chunk_json = json.loads(decoded_chunk)