Objective To explore the effect of psychological capital on nurses′job performance and satisfaction and the mediating role of positive emotion. Methods 523 nurses employed in eight hospitals in Anhui province were selected through multistage sampling and interviewed using questionnaires . Structural equation modeling was used to test the proposed relationships. Results Nurses′psychological capital was significantly positive correlated with positive emotion (r=0.473), job performance (r=0.505) and satisfaction (r=0.358), all P<0.01. Nurses′positive emotion was also significantly positive correlated with job performance (r=0.343) and satisfaction (r=0.452) , all P<0.01. The mediating test showed that nurses′positive emotion acted as a partial mediator between psychological capital and job satisfaction while medium effect accounting for 61.5%(0.24/0.39) of the whole effect. Nurses′positive emotion also played a role of being a partial mediator between psychological capital and two aspects of job performance, professional development ability and scientific research innovation ability,while medium effect accounting for 10.0%(0.06/0.60) and 12.9%(0.08/0.62) of the whole effect, respectively. Conclusions Psychological capital affects nurses′job performance and satisfaction and suggests nurses′positive emotion play a role of being a partial mediator in this relationship.