diff --git a/api/core/rag/retrieval/dataset_retrieval.py b/api/core/rag/retrieval/dataset_retrieval.py
index a25bc65646..cd4af72832 100644
--- a/api/core/rag/retrieval/dataset_retrieval.py
+++ b/api/core/rag/retrieval/dataset_retrieval.py
@@ -1012,7 +1012,7 @@ class DatasetRetrieval:
     def _process_metadata_filter_func(
         self, sequence: int, condition: str, metadata_name: str, value: Optional[Any], filters: list
     ):
-        if value is None:
+        if value is None and condition not in ("empty", "not empty"):
             return
 
         key = f"{metadata_name}_{sequence}"
diff --git a/api/core/workflow/nodes/knowledge_retrieval/knowledge_retrieval_node.py b/api/core/workflow/nodes/knowledge_retrieval/knowledge_retrieval_node.py
index 7303b68501..e8afe6aa4a 100644
--- a/api/core/workflow/nodes/knowledge_retrieval/knowledge_retrieval_node.py
+++ b/api/core/workflow/nodes/knowledge_retrieval/knowledge_retrieval_node.py
@@ -572,7 +572,7 @@ class KnowledgeRetrievalNode(BaseNode):
     def _process_metadata_filter_func(
         self, sequence: int, condition: str, metadata_name: str, value: Optional[Any], filters: list
     ):
-        if value is None:
+        if value is None and condition not in ("empty", "not empty"):
             return
 
         key = f"{metadata_name}_{sequence}"