diff --git a/docs/en/unit/sonic.md b/docs/en/unit/sonic.md
index 6446459a..342c6324 100644
--- a/docs/en/unit/sonic.md
+++ b/docs/en/unit/sonic.md
@@ -8,18 +8,23 @@
 
 **Ultrasonic** is an ultrasonic distance measuring sensor unit, with the capability of simultaneous reception and transmission. The ultrasonic probe has a sound frequency of 40KHz, a direction angle of ±20 ° and an accuracy of 1mm. The internal part is calculated by an RCWL-9600 ultrasonic distance measuring chip, and the measurement results can be directly obtained through IIC interface (0x57). The effective distance is 20-1500mm.
 
-### Product Features
+## Product Features
 
 - Split transceiver
 - Effective distance 20-1500mm
 - Wide angle range
 - IIC communication, result output directly
 
-### Includes
+## Includes
 
 - 1x Ultrasonic Unit
 - 1x Grove Cable(20cm)
 
+## Application
+
+- Measuring distance
+- Avoid obstacles
+
 ## Specification
 
 <table>
diff --git a/docs/zh_CN/unit/sonic.md b/docs/zh_CN/unit/sonic.md
index edd5dd6a..a06ffe39 100644
--- a/docs/zh_CN/unit/sonic.md
+++ b/docs/zh_CN/unit/sonic.md
@@ -8,18 +8,23 @@
 
 **Ultrasonic** 是一款超声波测距传感器单元，采用收发分体式设计，其中超声波探头的声波频率40Khz，方向角±20°，精度可达1mm,内部由RCWL-9600超声波测距芯片运算，通过IIC接口(0x57)可直接获得测量结果。测量有效距离为20-1500mm。
 
-### 产品特性
+## 产品特性
 
 - 分体式收发
 - 有效距离1500mm
 - 方向角范围广
 - IIC通讯，结果直接输出
 
-### 包含
+## 包含
 
 -  1x Ultrasonic Unit
 -  1x Grove连接线(20cm)
 
+## 应用
+
+- 距离测量
+- 避障
+
 ## 规格参数
 
 <table>