To explore the relationship among psychological capital， social support and learning burnout of medical graduate students. A total of 249 medical graduate students were surveyed with psychological capital questionnaire， social support scale and Maslach burnout inventory general survey（MBI?GS）. 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. Education departments should strengthen the cultivation of positive psychological capital of medical postgraduates to prevent and reduce the occurrence of learning burnout.