diff --git a/api/core/rag/datasource/retrieval_service.py b/api/core/rag/datasource/retrieval_service.py
index 0fda35100c..e32b1ddb33 100644
--- a/api/core/rag/datasource/retrieval_service.py
+++ b/api/core/rag/datasource/retrieval_service.py
@@ -542,7 +542,7 @@ class RetrievalService:
                     child_chunks = None
 
                 if child_chunks:
-                    child_chunks = sorted(child_chunks, key=lambda x: x.get, reverse=True)
+                    child_chunks = sorted(child_chunks, key=lambda x: x.get("score", 0.0), reverse=True)
 
                 # Extract files, ensuring it's a list or None
                 files = record.get("files")