Using Cluster sampling on 9522 postgraduate freshmen, all data of SCL-90 was counted and analyzed by SPSS 21.0. On the whole, the mental health of postgraduates was not bad(The rate of positive was 1.0 ~ 8.4％), obsessive compulsive, interpersonal sensitivity and anxiety symptom were the top three mental illness. The data of female, rural, non-only-child, post-90 and only-child of post-90 postgraduate freshmen was higher than the data of male, urban, only-child, post-80 and only-child of post-80 postgraduate freshmen. Many differences between them were more or most significant(p＜0.01or 0.001). The mental health of postgraduate freshmen still had many obstacles. So measures should be taken to reinforce it.