Abstract: ObjectiveTo explore the mediation effect of self-efficacy on the relationship between perfectionism and psychological well-being in medical students.MethodsTotally 761 medical school students completed Chinese Frost's Multidimensional Perfectionism Scale(FMPS),General Self-Efficacy Scale(GSES),and General Happiness Questionnaire.ResultsSignificant correlations were found among perfectionism,self-efficacy,and physical well-being(P<0.05). Regression analyses indicated that self-efficacy had a partially mediate effect(P<0.05).After introducing the general selfefficacy,the △R² of positive perfectionism was 20.9% and the standardized coefficient was reduced from 0.284 to 0.144, with significant difference(P>0.05).The △R² for negative perfectionism was 24.7% and the standardized coefficient was reduced from -0.227 to -0.171(P>0.05 after the induction of general self-efficacy).ConclusionSelf-efficacy had a partially mediate effect on perfectionism and psychological well-being.