diff --git a/api/core/rag/retrieval/dataset_retrieval.py b/api/core/rag/retrieval/dataset_retrieval.py
index cdaca8387d..12868d6ae4 100644
--- a/api/core/rag/retrieval/dataset_retrieval.py
+++ b/api/core/rag/retrieval/dataset_retrieval.py
@@ -429,7 +429,7 @@ class DatasetRetrieval:
                         top_k=top_k,
                         score_threshold=retrieval_model.get("score_threshold", 0.0)
                         if retrieval_model["score_threshold_enabled"]
-                        else None,
+                        else 0.0,
                         reranking_model=retrieval_model.get("reranking_model", None)
                         if retrieval_model["reranking_enable"]
                         else None,
diff --git a/api/core/tools/tool/dataset_retriever/dataset_multi_retriever_tool.py b/api/core/tools/tool/dataset_retriever/dataset_multi_retriever_tool.py
index 067600c601..6073b8e92e 100644
--- a/api/core/tools/tool/dataset_retriever/dataset_multi_retriever_tool.py
+++ b/api/core/tools/tool/dataset_retriever/dataset_multi_retriever_tool.py
@@ -179,7 +179,7 @@ class DatasetMultiRetrieverTool(DatasetRetrieverBaseTool):
                         top_k=self.top_k,
                         score_threshold=retrieval_model.get("score_threshold", 0.0)
                         if retrieval_model["score_threshold_enabled"]
-                        else None,
+                        else 0.0,
                         reranking_model=retrieval_model.get("reranking_model", None)
                         if retrieval_model["reranking_enable"]
                         else None,
diff --git a/api/core/tools/tool/dataset_retriever/dataset_retriever_tool.py b/api/core/tools/tool/dataset_retriever/dataset_retriever_tool.py
index ad533946a1..8dc60408c9 100644
--- a/api/core/tools/tool/dataset_retriever/dataset_retriever_tool.py
+++ b/api/core/tools/tool/dataset_retriever/dataset_retriever_tool.py
@@ -72,7 +72,7 @@ class DatasetRetrieverTool(DatasetRetrieverBaseTool):
                     top_k=self.top_k,
                     score_threshold=retrieval_model.get("score_threshold", 0.0)
                     if retrieval_model["score_threshold_enabled"]
-                    else None,
+                    else 0.0,
                     reranking_model=retrieval_model.get("reranking_model", None)
                     if retrieval_model["reranking_enable"]
                     else None,
diff --git a/api/services/hit_testing_service.py b/api/services/hit_testing_service.py
index a9f963dbac..3dafafd5b4 100644
--- a/api/services/hit_testing_service.py
+++ b/api/services/hit_testing_service.py
@@ -42,7 +42,7 @@ class HitTestingService:
             top_k=retrieval_model.get("top_k", 2),
             score_threshold=retrieval_model.get("score_threshold", 0.0)
             if retrieval_model["score_threshold_enabled"]
-            else None,
+            else 0.0,
             reranking_model=retrieval_model.get("reranking_model", None)
             if retrieval_model["reranking_enable"]
             else None,