Objective: To explore the relationship among social support, self-efficacy, peer pressure and physical exercise behavior and to provide a reference for subjective initiative of college students in physical exercise. Methods: Questionnaire survey regarding social support, peer pressure and self-efficacy, as well as physical exercise behavior was administered among 1 189 students from 3 colleges and universities in Henan Province during August to October 2019. Results: Peer pressure score was (18.72±4.02), subjective support score was (14.76±3.46), objective support score was (10.98±2.53), utilization score for support was (11.20±3.12), self-efficacy score was (36.79±8.00), physical exercise behavior score was (21.72±4.75). Subjective support, objective support, utilization of support, peer pressure, self-efficacy and college students ’ physical exercise behavior were significantly positively correlated(P<0.05). Structural equation model showed that subjective support, objective support, utilization of support, peer pressure, and self-efficacy significantly positively associated with physical exercise behavior,with standardization coefficients of 0.08, 0.12, 0.13, 0.40, 0.90(P<0.05), respectively. Self-efficacy has significant mediating effect on peer pressure, subjective support, objective support, utilization of support and physical exercise behavior of college students used, with standardized effect quantities being 55.36%, 90.73%, 85.88%, 87.92%, respectively. Conclusion College students’ physical exercise behavior is closely related to social support, peer pressure and self-efficacy. Social support has a significant impact on college students’ physical exercise behavior, and self-efficacy, while self-efficacy and peer pressure all have a positive effect on college students’ physical exercise behavior.