To explore the influence mechanism of psychological capital on career success, a questionnaire survey was conducted among 288 research and development (R&D) personnel of computer information technology in China. The results showed that psychological capital, career commitment, person-organization fit, total score and each dimension of career success were significantly positively correlated with each other; psychological capital significantly positively predicts objective and subjective career success, and the predictive effect of both can be realized through the mediating role of career commitment; in the second half of the mediated path between psychological capital and subjective career success, career commitment is regulated by person-organization fit. Compared with individuals with a low level of person-organization fit, individuals with a high level of person-organization fit have a stronger mediating effect on the relationship between psychological capital and subjective career success.