diff --git a/internal/querynodev2/delegator/delegator_data.go b/internal/querynodev2/delegator/delegator_data.go
index 33ea916414b07..c0b87fd284b0a 100644
--- a/internal/querynodev2/delegator/delegator_data.go
+++ b/internal/querynodev2/delegator/delegator_data.go
@@ -1004,12 +1004,12 @@ func (sd *shardDelegator) buildBM25IDF(req *internalpb.SearchRequest) (float64,
 	proto.Unmarshal(req.GetPlaceholderGroup(), pb)
 
 	if len(pb.Placeholders) != 1 || len(pb.Placeholders[0].Values) == 0 {
-		return 0, merr.WrapErrParameterInvalidMsg("please provide varchar for bm25")
+		return 0, merr.WrapErrParameterInvalidMsg("please provide varchar for BM25 Function based search")
 	}
 
 	holder := pb.Placeholders[0]
 	if holder.Type != commonpb.PlaceholderType_VarChar {
-		return 0, fmt.Errorf("can't build BM25 IDF for data not varchar")
+		return 0, merr.WrapErrParameterInvalidMsg(fmt.Sprintf("please provide varchar for BM25 Function based search, got %s", holder.Type.String()))
 	}
 
 	str := funcutil.GetVarCharFromPlaceholder(holder)
diff --git a/tests/python_client/testcases/test_full_text_search.py b/tests/python_client/testcases/test_full_text_search.py
index 97803999051fa..b3445f75560b7 100644
--- a/tests/python_client/testcases/test_full_text_search.py
+++ b/tests/python_client/testcases/test_full_text_search.py
@@ -3089,7 +3089,7 @@ def test_search_for_full_text_search_with_invalid_search_data(
             search_data = cf.gen_vectors(nb=nq, dim=1000, vector_data_type="FLOAT_VECTOR")
         log.info(f"search data: {search_data}")
         error = {ct.err_code: 65535,
-                 ct.err_msg: "can't build BM25 IDF for data not varchar"}
+                 ct.err_msg: "please provide varchar for BM25 Function based search"}
         collection_w.search(
             data=search_data,
             anns_field="text_sparse_emb",