Code-switching between English and Chinese is a common phenomenon in the Chinese overseas students’ daily conversation. It is a complex issue which involves many aspects such as linguistics, psychology, sociology. This paper is mainly based on Myers-Scotton’s relative theories. It emphasizes on the sociolinguistic aspect to describe the conversation which contains code-switching as well as digging the reasons and the motivations of code-switching. Code-switching between English and Chinese is a common phenomenon in the Chinese overseas students’ daily conversation. It is a complex issue which involves many aspects such as linguistics, psychology, sociology. This paper is mainly based on Myers-Scotton’s relative theories. It emphasizes on the sociolinguistic aspect to describe the conversation which contains code-switching as well as digging the reasons and the motivations of code-switching.