This study used the international 12-item general health questionnaire (GHQ-12) to survey 2578 postgraduates in three medical schools in Shanghai. The results show that the psychology of postgraduates in medical schools is generally “sub-healthy.” 55.4% of the participants are in a state of excessive psychological stress, and 38.2% of the participants have or are developing into mental illness. Compared with the data published by European scholars, the pressure on graduate students in medical schools in the country is greater, and the psychological “sub-health” is more serious. The above results all remind that schools must strengthen their attention to the mental health of graduate students in the medical school, take practical actions to help them complete their studies with a healthy attitude, and eventually grow into the pillars of socialism.