diff --git a/internal/datacoord/index_service.go b/internal/datacoord/index_service.go
index f182619297..1071381b35 100644
--- a/internal/datacoord/index_service.go
+++ b/internal/datacoord/index_service.go
@@ -55,7 +55,7 @@ func (s *Server) serverID() int64 {
 	return 0
 }
 
-func (s *Server) getFieldNameByID(schema *schemapb.CollectionSchema, fieldID int64) (string, error) {
+func (s *Server) defaultIndexNameByID(schema *schemapb.CollectionSchema, fieldID int64) (string, error) {
 	for _, field := range schema.GetFields() {
 		if field.FieldID == fieldID {
 			return field.Name, nil
@@ -184,7 +184,7 @@ func (s *Server) CreateIndex(ctx context.Context, req *indexpb.CreateIndexReques
 
 	if req.GetIndexName() == "" {
 		indexes := s.meta.indexMeta.GetFieldIndexes(req.GetCollectionID(), req.GetFieldID(), req.GetIndexName())
-		fieldName, err := s.getFieldNameByID(schema, req.GetFieldID())
+		fieldName, err := s.defaultIndexNameByID(schema, req.GetFieldID())
 		if err != nil {
 			log.Warn("get field name from schema failed", zap.Int64("fieldID", req.GetFieldID()))
 			return merr.Status(err), nil
diff --git a/internal/proxy/util.go b/internal/proxy/util.go
index e0bfccfc32..629a0f5155 100644
--- a/internal/proxy/util.go
+++ b/internal/proxy/util.go
@@ -1620,6 +1620,10 @@ func translateOutputFields(outputFields []string, schema *schemaInfo, removePkFi
 	return resultFieldNames, userOutputFields, userDynamicFields, userRequestedPkFieldExplicitly, nil
 }
 
+func validCharInIndexName(c byte) bool {
+	return c == '_' || c == '[' || c == ']' || isAlpha(c) || isNumber(c)
+}
+
 func validateIndexName(indexName string) error {
 	indexName = strings.TrimSpace(indexName)
 
@@ -1641,7 +1645,7 @@ func validateIndexName(indexName string) error {
 	indexNameSize := len(indexName)
 	for i := 1; i < indexNameSize; i++ {
 		c := indexName[i]
-		if c != '_' && !isAlpha(c) && !isNumber(c) {
+		if !validCharInIndexName(c) {
 			msg := invalidMsg + "Index name can only contain numbers, letters, and underscores."
 			return errors.New(msg)
 		}