This article investigates the relationship between the number of informational channels and over-education in the outcome of job search, using the survey data of postgraduates in China. The empirical results show: (1) the more the informational channels of job search are used, the lower the probability and the less the intensity of over-education will be; (2) graduates from prestigious "985" universities have lower probability and less intensity of over-education than those of their counterparts from "none-985" universities. Based on the findings above, we argue that helping graduates to get more job information and improving the quality of universities will lighten the problem of the over-education under the situation of great higher education expansion.