Objective To explore the mediating effect of professional identity on professional benefit and work engagement among nurses,and to provide reference for clinical nursing management. Methods Totally 498 nurses were selected conveniently, then they were investigated using the Nurse Professional Identity Rating Scale, the Nurse Professional Benefit Questionnaire and the Work Input Scale. Results Nurses′ total score of professional identity, professional benefit and work engagement was （100.95±15.21）、（129.86±16.40）、（63.88±22.94） respectively. There were significant positive correlations among the three variables （P＜0.01 for all）, professional identity played a part of mediating effect between professional benefit and work engagement, the mediating effect accounted for 54.56% of the total effect. Conclusion Improving clinical nurses′ professional identity could enhance their professional benefit, then increase their work engagement level.