There is a deviation in the positioning of mobile phone. Wechat users in Yunnan are searched because of the positioning deviation caused by poor or unstable GPS function of mobile phones. It is recommended to use the WeChat function in a place with good information. Wechat is a free application launched by Tencent on 2011121,which provides instant messaging service for intelligent terminals. It was created by the product team of Tencent Guangzhou R&D Center led by Zhang Xiaolong.