Abstract: Objective To investigate the relationships among psychological capital，organizational identification and job performance of clinical nurses in a tertiary hospital. Methods Totally 242 clinical nurses from a tertiary hospital were investigated by using Organizational Identification Questionnaire，Psychological Capital Scale and Job Performance Questionnaire. Results The scores of nurses’ organizational identity，psychological capital and job performance were 3.98±0.66，3.64±0.50 and 3.71±0.43 respectively. The correlation coefficients among the three variables ranged from 0.351 to 0.628. Psychological capital played a mediating role between organizational identity and job performance （Z=3.13，P<0.01）. Organizational identity and psychological capital jointly explained 48.5% of the total variation in job performance. Conclusion Organizational identity and psychological capital are the influencing factors of job performance. Organizational identity can not only directly affect job performance，but also indirectly affect psychological performance through psychological capital. Nursing managers should take measures to improve nurses’ organizational identity and psychological capital in order to improve their work performance.

Key words: Nurses, Questionnaires, Organizational identity, Psychological capital, Job performance