diff --git a/glist/linkedlist.go b/glist/linkedlist.go
index fdacafe..77424f8 100644
--- a/glist/linkedlist.go
+++ b/glist/linkedlist.go
@@ -230,11 +230,24 @@ func (l *LinkedList[E]) PullFront() *E {
 
 // Iterator 获取该链表的迭代器
 func (l *LinkedList[E]) Iterator() Iterator[E] {
-	return &LinkedListIterator[E]{next: l.First}
+	return &LinkedListIterator[E]{
+		reverse: false,
+		next:    l.First,
+	}
+}
+
+// ReverseIterator 获取反向迭代器
+func (l *LinkedList[E]) ReverseIterator() Iterator[E] {
+	return &LinkedListIterator[E]{
+		reverse: true,
+		next:    l.Last,
+	}
 }
 
 type LinkedListIterator[E any] struct {
-	next *Node[E]
+	//是否反向,如果为true,则是从尾部向头部迭代
+	reverse bool
+	next    *Node[E]
 }
 
 func (l *LinkedListIterator[E]) Has() bool {
@@ -246,6 +259,10 @@ func (l *LinkedListIterator[E]) Next() E {
 	if e == nil {
 		panic("iterator is empty.")
 	}
-	l.next = e.Next
+	if l.reverse {
+		l.next = e.Prev
+	} else {
+		l.next = e.Next
+	}
 	return e.Element
 }
diff --git a/glist/list.go b/glist/list.go
index 0f1da8d..ca26569 100644
--- a/glist/list.go
+++ b/glist/list.go
@@ -20,6 +20,8 @@ type List[E any] interface {
 	Set(index uint, element E) bool
 	// Iterator 获取列表的迭代器
 	Iterator() Iterator[E]
+	// ReverseIterator 反向迭代器,从尾部向前迭代
+	ReverseIterator() Iterator[E]
 }
 
 // Queue 队列
diff --git a/srt.go b/srt.go
index e9c5a2d..8142b3f 100644
--- a/srt.go
+++ b/srt.go
@@ -19,7 +19,7 @@ const (
 )
 
 type SRTContent struct {
-	//序号，从1开始
+	//序号，从1开始,只在写入文件的时候设置这个属性
 	Index int
 	//开始时间，单位毫秒
 	Start int
@@ -73,7 +73,7 @@ func LrcToSrt(lrc *LRC) *SRT {
 	for it := lrc.LrcList.Iterator(); it.Has(); {
 		lrcNode := it.Next()
 		srtContent := &SRTContent{
-			Index: index,
+			Index: 0,
 			Start: lrcNode.time,
 			Text:  lrcNode.content,
 		}
@@ -159,7 +159,9 @@ func (s *SRT) mergeUp(other *SRT) {
 func (s *SRT) mergeBottom(other *SRT) {
 	oq := other.Content
 	if oq.IsNotEmpty() {
-		s.Content.PushFront(*(oq.PullBack()))
+		for it := other.Content.ReverseIterator(); it.Has(); {
+			s.Content.PushFront(it.Next())
+		}
 	}
 }
 
@@ -179,8 +181,12 @@ func (s *SRT) Write(dst io.Writer) error {
 	//6KB的缓冲
 	bufSize := 1024 * 6
 	writer := bufio.NewWriterSize(dst, bufSize)
+	index := 1
 	for it := s.Content.Iterator(); it.Has(); {
-		_, err := writer.WriteString(it.Next().String())
+		content := it.Next()
+		content.Index = index
+		index++
+		_, err := writer.WriteString(content.String())
 		if err != nil {
 			return err
 		}