diff --git a/sync.go b/sync.go
index 9e1cb8c1..adc2d859 100644
--- a/sync.go
+++ b/sync.go
@@ -235,15 +235,6 @@ func (session *Session) SyncWithOptions(opts SyncOptions, beans ...interface{})
 				}
 			}
 
-			if oriIndex != nil && oriIndex.Type != index.Type {
-				sql := engine.dialect.DropIndexSQL(tbNameWithSchema, oriIndex)
-				_, err = session.exec(sql)
-				if err != nil {
-					return nil, err
-				}
-				oriIndex = nil
-			}
-
 			if oriIndex == nil {
 				addedNames[name] = index
 			}
diff --git a/tests/sync_test.go b/tests/sync_test.go
new file mode 100644
index 00000000..dedd3343
--- /dev/null
+++ b/tests/sync_test.go
@@ -0,0 +1,34 @@
+// Copyright 2023 The Xorm Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package tests
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type TestSync1 struct {
+	Id      int64
+	ClassId int64 `xorm:"index"`
+}
+
+func (TestSync1) TableName() string {
+	return "test_sync"
+}
+
+type TestSync2 struct {
+	Id      int64
+	ClassId int64 `xorm:"unique"`
+}
+
+func (TestSync2) TableName() string {
+	return "test_sync"
+}
+
+func TestSync(t *testing.T) {
+	assert.NoError(t, testEngine.Sync(new(TestSync1)))
+	assert.NoError(t, testEngine.Sync(new(TestSync2)))
+}