Over education is not only happening in the Western countries. Since the enrollment of Chinese universities, the incidence of over-education has been significantly improved, and the study of over-education has been promoted. This paper begins with the definition of over-education, and combs the relevant research on over-education in the 1930s. It introduces the methods of over-education commonly used in China, the incidence of over-education, the impact of over-education on income. This paper also analyzes the problems of over-education.