Objective: To investigate the mediating role of leaning engagement in the relationship between professional identity and career maturity. Methods: 711 pre-service kindergarten teachers completed the Professional Identification Scale, the College Students' Career Maturity Questionnaire and the Utrecht Work Engagement Scale-student. Results: 1) There are significant difference in professional identity and career maturity on grades, different level of parents' education and whether part-time work. 2) Professional identity, career maturity, and learning engagement were significantly correlated with each other. 3) Career maturity partially mediated the relationship between professional identity and learning engagement. Conclusion: Professional identity directly influences learning engagement, and also influences learning engagement through the partial mediating effects of career maturity.