Background: Workplace violence has been recognized globally as a serious occupational hazard in health services occupations, and existing studies have identified that workplace violence can significantly lead to depression. Interpersonal trust, an important topic, also has been proved associated with workplace violence and depression. However, the moderating effect of interpersonal trust has not been tested before, which can help us to further understand the effect mechanism of workplace violence on depression. Method: In the current study, we collected 3,426 valid questionnaires based on a cross-sectional design among medical staff in Chinese hospitals. Depression, workplace violence, interpersonal trust, social support, physical diseases, and some other social-demographic variables were evaluated. Results: The data analyzed in the current study supported that there were 52.2% of medical staff experienced workplace violence before. Experiencing verbal violence (b=2.99, p<0.001), experiencing physical violence (b=3.70, p<0.01), experiencing both kinds of the violence (b=4.84, p<0.001), high level of interpersonal trust (b=0.22, p<0.001), nursing (b=1.10, p<0.05), manager (b=-1.72, p<0.001), suffering physical disease (b=3.35, p<0.001), social support (b=-0.23, p<0.001) were significantly associated with depression. Interpersonal trust had a partial mediating effect on the relationship between workplace violence and depression. Conclusion: Interpersonal trust can be a mediator between workplace violence and depression. Some potential strategies would be beneficial to promoting the mental health status among medical staff.