Objective: To explore the relationship among psychological capital, social support and learning burnout of medical graduate students. Methods: A total of 249 medical graduate students were surveyed with Psychological Capital Questionnaire, Social support scale and Maslach Burnout Inventory General Survey (MBI-GS). Results: The score of burnout among medical postgraduates students was 2.49±1.04. 13.6% students have severe learning burnout. There were significant negative correlation between psychological capital or social support and learning burnout or its factors (P＜0.05). Multivariate linear regression analysis showed optimism and utilization of social support could effectively predict learning burnout, and these variables explained 35.3% variance of learning burnout in medical graduate students. Conclusion: Education departments should strengthen the cultivation of positive psychological capital of medical postgraduates to prevent and reduce the occurrence of learning burnout.