diff --git a/notes/src/SUMMARY.md b/notes/src/SUMMARY.md
index 356c249..7d12da2 100644
--- a/notes/src/SUMMARY.md
+++ b/notes/src/SUMMARY.md
@@ -74,4 +74,5 @@
 - [二分查找](./bin_search.md)
 - [KMP](./kmp.md)
 - [单调队列](./stack_and_queue.md)
+- [二叉树遍历](./btree_iter.md)
 - [合并两个有序链表](./merge_two_sorted_linked_lists.md)