Abstract: Objective To examine the relation between occupational stress and job satisfaction and mediating effect of psychological capital on the relation among peasant workers.Methods With stratified random cluster sampling, totally 899 peasant workers from construction sites and private enterprises in Anhui province were recruited and measured with Effort-Reword Imbalance Questionnaire, Minnesota Satisfaction Questionnaire and Psychological Capital Questionnaire.Results Among the participants, the average score of job satisfaction was 65.04±10.91;the average psychological capital scores were 22.1±5.34 for self-confidence, 23.7±4.67 for hope, 23.5±3.61 for toughness, and 22.6±2.69 for optimism, respectively.The job satisfaction was reveresely correlated with external effort, but positively correlated to reword and inner effort(P<0.001 for all).The contribution of occupational stress to job satisfaction was 30.6%.The contribution of psychological capital to job satisfaction was 22.5% with a mediating effect.Conclusion Job satisfaction is at a general level;external effort, reword and inner effort are significant predictors for job satisfaction and psychological capital is a mediating factor among reword, inner effort and job satisfaction among peasant workers.