diff --git a/book/contents/async/getting-started.md b/book/contents/async/getting-started.md
index b0daad22..19141ba9 100644
--- a/book/contents/async/getting-started.md
+++ b/book/contents/async/getting-started.md
@@ -61,7 +61,7 @@
 | 操作 | async | 线程 |
 | ---- | ----- | ---- |
 | 创建 | 0.3微妙 | 17微妙 |
-| 线程切换 ｜ 0.2微妙 | 1.7微妙 |
+| 线程切换 | 0.2微妙 | 1.7微妙 |
 
 可以看出，`async` 在线程切换的开销显著低于多线程，对于 IO 密集的场景，这种性能开销累计下来会非常可怕！