Objective To investigate the hardiness level of military medical students and to explore its influencing factors. Methods A total of 543 medical students from a military university were investigated with Chinese adult hardiness personality scale, general self-efficacy scale and perceived social support scale. Multiple linear regression model was performed to explore the predictive factors of hardiness of medical students. Results A total of 543 questionnaires were sent out, and 504 valid questionnaires were collected, with an effective recovery rate of 92.8%. The total score of hardiness was 72.91±13.03, and the average score of the items was 2.70±0.48. The average score of resilience items was the highest (2.81±0.56), followed by control (2.70±0.51), commitment (2.69±0.55) and challenge (2.62±0.55). Frequency of extracurricular activities (β=0.121, P=0.002), self-efficacy (β=0.432, P<0.01) and friend support (β=0.170, P<0.01) were predictive factors of hardiness, and they could explain 27.5% variances of hardiness in military medical students. Conclusion The hardiness of military medical students is relatively low and need to be improved. Encouraging the students to participate in extracurricular activities, promoting their self-efficacy and increasing their friend support may help to upgrade the hardiness of military medical students.