As a kind of communicative tool, Wechat becomes more and more necessary among people. Wechat can be used for communicating, learning and even showing one’s personal feelings. In recent years, language used in Wechat attracts more and more linguists’ attention. This article will do empirical research on Chinese and English code-switching used in Wechat by 10 English majors based on theories of social linguistics. Based on Poplack’s classification of code- switching, Syntactic features and behind motivations of Chinese and English code-switching will be explored as well.