diff --git a/internal/proxy/search_util.go b/internal/proxy/search_util.go
index 2d873a23da..3eab95cb26 100644
--- a/internal/proxy/search_util.go
+++ b/internal/proxy/search_util.go
@@ -347,11 +347,11 @@ func parseGroupByInfo(searchParamsPair []*commonpb.KeyValuePair, schema *schemap
 	if groupByFieldName != "" {
 		fields := schema.GetFields()
 		for _, field := range fields {
-			if field.GetNullable() {
-				ret.err = merr.WrapErrParameterInvalidMsg(fmt.Sprintf("groupBy field(%s) not support nullable == true", groupByFieldName))
-				return ret
-			}
 			if field.Name == groupByFieldName {
+				if field.GetNullable() {
+					ret.err = merr.WrapErrParameterInvalidMsg(fmt.Sprintf("groupBy field(%s) not support nullable == true", groupByFieldName))
+					return ret
+				}
 				groupByFieldId = field.FieldID
 				break
 			}
diff --git a/internal/proxy/task_search_test.go b/internal/proxy/task_search_test.go
index c0cbbeefc6..5b5e618a2f 100644
--- a/internal/proxy/task_search_test.go
+++ b/internal/proxy/task_search_test.go
@@ -2520,6 +2520,28 @@ func TestTaskSearch_parseSearchInfo(t *testing.T) {
 		searchInfo := parseSearchInfo(normalParam, schema, nil)
 		assert.Nil(t, searchInfo.planInfo)
 		assert.ErrorIs(t, searchInfo.parseError, merr.ErrParameterInvalid)
+
+		normalParam = getValidSearchParams()
+		normalParam = append(normalParam, &commonpb.KeyValuePair{
+			Key:   GroupByFieldKey,
+			Value: "string_field",
+		})
+		fields = make([]*schemapb.FieldSchema, 0)
+		fields = append(fields, &schemapb.FieldSchema{
+			FieldID: int64(101),
+			Name:    "string_field",
+		})
+		fields = append(fields, &schemapb.FieldSchema{
+			FieldID:  int64(102),
+			Name:     "null_field",
+			Nullable: true,
+		})
+		schema = &schemapb.CollectionSchema{
+			Fields: fields,
+		}
+		searchInfo = parseSearchInfo(normalParam, schema, nil)
+		assert.NotNil(t, searchInfo.planInfo)
+		assert.NoError(t, searchInfo.parseError)
 	})
 	t.Run("check iterator and topK", func(t *testing.T) {
 		normalParam := getValidSearchParams()