diff --git a/API_Reference_EN.md b/API_Reference_EN.md
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--- a/API_Reference_EN.md
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 # kc868-arduino-library  API Reference
+[English](https://github.com/hzkincony/kc868-arduino-library/blob/main/API_Reference_EN.md)|[中文](https://github.com/hzkincony/kc868-arduino-library/blob/main/API_Reference_CN.md)
+
+---
 
 This library for KC868-H32B Pro smart controller based on ESP32 chip, you should include "KC868.h" in your code as follows: