Objective　To explore the impact of mentors' behaviors on the professional identity of medical students during the internship. Methods　Based on the data of the China Medical Students Survey in 2020

a research was conducted on 25 557 medical graduates from 104 universities in China. The Wilcoxon rank-sum test and multiple linear regression were used to analyze the impact of mentors' behaviors on the professional identity of medical students during the internship. Results　More than 70% of medical students believed that the clinical mentors they met during their internship had positive medical and teaching behaviors. If students believed that clinical mentors were enthusiastic

responsible for their work

highlighted role modeling and paid attention to their behaviors in teaching

the scores of professional identity would be 3.027

0.445

0.840 and 1.234 points greater than if they did not respectively (all P<0.001). Conclusion　The students have generally good evaluation on mentors' behavior during the internship. The positive medical and teaching behaviors of mentors have a positive impact on the professional identity of medical students and the impact of enthusiasm is the greatest. Medical institutions should provide complete institutional support and standardize the behavior of clinical teachers in order to enhance the professional identity of medical students.