Objective To explore the influencing factors of medical staff’s preventive behaviors of occupational exposure using health belief model. Methods A questionnaire was used to investigate the health beliefs and prevention-related behaviors of medical staff in Shuguang Hospital Affilliated to Shanghai University of Traditional Chinese Medicine from July 2018 to June 2019. The preventive behaviors and health beliefs of health workers with different occupational categories and working years were analyzed descriptively, and the influence of health beliefs on preventive behaviors was analyzed with multiple linear regression. Results There were 400 copies of questionnaire dispatched and 384 recovered. Among the survey respondents, 258 (67.19%) were females, 169 (44.01%) were aged 20-30 years, and 203 (52.86%) had worked for 5 or less years; 158 (41.15%) had sharp injury experience, 171 (44.53%) had experience of exposure to blood or body fluids, and 290 (75.52%) were actively immunized by injecting vaccines. The total score of compliance with standard preventive behaviors of the 384 respondents was 6.94±3.12. The scores of perceived susceptibility, perceived severity, perceived barriers, perceived benefits, and perceived self-efficacy were 24.87±4.56, 31.27±5.92, 16.50±5.77, 36.06±5.60, and 15.27±2.98, respectively. The total score of health beliefs was 123.97±15.91. The compliance with standard preventive behaviors and total score of health beliefs of logistics staff were lower than those of other respondents (P<0.05). The scores of perceived barriers of medical technicians and clinicians were significantly higher than that of nurses (P<0.05). The scores of perceived benefits and perceived self-efficacy of clinicians were lower than those of nurses (P<0.05). Respondents who had worked for 6-10 years had better compliance with standard preventive behaviors than interns and the ones who had worked for 11-15 years (P<0.05), and had a lower total score of health beliefs than the ones who had worked for over 16 years (P<0.05). Respondents who had worked for over 16 years had better scores of perceived benefits and perceived self-efficacy (P<0.05), and had a lower score of perceived barriers (P<0.05). The results of multiple linear regression analysis showed that gender [nonstandardized partial regression coefficient (b)=–0.644, 95% confidence interval (CI) (–1.162, –0.125), P=0.015], educational background [b=1.367, 95%CI (1.245, 1.587), P<0.001], and score of perceived barriers [b=0.044, 95%CI (0.004, 0.084), P=0.031] were influencing factors of medical staff’s preventive behavior compliance. Conclusions The score of perceived barriers is a main factor that prevents medical staff from implementing standard preventive measures. In the occupational exposure training program, it may be effective to help medical staff establish good standard prevention habits by improving the awareness of obstacles.