At this stage, the development of Internet has entered a flourishing state and makes all kinds of social information derive diversified network services in the exchange relying on the spread of PC, smart phones and other civilian facilities. While social network characterized by its authenticity, convenience and interactivity is popular among students. However, social network also brings a lot of psychological problems for college students, which impacts on cognition, emotion, characters and other aspects of college students. This paper focuses on the impact of social network on college students' mental health, and discuss how to deal with the psychological impact of social networks on college students.