diff --git a/migrator/migrator.go b/migrator/migrator.go
index d4989410..afc3e44b 100644
--- a/migrator/migrator.go
+++ b/migrator/migrator.go
@@ -440,7 +440,7 @@ func (m Migrator) MigrateColumn(value interface{}, field *schema.Field, columnTy
 	}
 
 	// check unique
-	if unique, ok := columnType.Unique(); ok && unique != field.Unique {
+	if unique, ok := columnType.Unique(); ok && !(unique == field.Unique || field.UniqueIndex == unique) {
 		// not primary key
 		if !field.PrimaryKey {
 			alterColumn = true