Abstract: Objective To explore the relationship between perceived social support, optimism, self-efficacy and depression among orthopedics inpatients, and to provide theoretical evidence for clinical intervention.Methods A total of 109 inpatients were recruited for a cross-sectional study from October to November in 2013 in Affiliated Shengjing Hospital of China Medical University.A general information questionnaire, Perceived Social Support Scale, Self-Efficacy Scale, Life Orientation Test, and Center for Epidemiologic Studies Depression Scale were applied in the inpatients with a self-administrated survey.Results The average score was 19.11±8.38 for depression, 65.31±13.19 for social support, 36.19±4.45 for optimism, and 28.81±5.96 for self-efficacy, respectively.There were significant differences in the scores of various dimensions of the scales between depressive and non-depressive group.The results of multivariate hierarchical regression analysis showed that supports from friends and society were inversely associated with depression, explaining 26.3%of variance for depression.After adding two mediator variables in the model, optimism played an absolute mediate role and negatively associated with depression(β=-0.393, P<0.001), explaining 14.3% of variance of depression.Self-efficacy was not a significant mediate varible.Conclusion Optimism as a mediate variable is a negative predicted factor between perceived social support and depression and could be benefit to health and mind of the inpatients.