Objective: To understand the AIDS knowledge of male college students who have sex experience and the influencing factors of high-risk sexual behaviors, so as to provide a basis for AIDS prevention and control on campus. Methods: A total of 5 718 male college students who have sex from 18 colleges and universities in Nanjing were investigated by stratified random cluster sampling method from April to June in 2019. Their AIDS knowledge and high-risk sexual behaviors were investigated and risk factors were analyzed. Results: Male college students had poor AIDS related knowledge and the incidence of high-risk sexual behaviors was 61.5%. Logistic regression analysis showed that the proportion of male college students with sexual orientation of bisexuality(OR=1.61), uncertainty (OR=2.41) and heterosexuality (OR=1.47) who had high-risk sexual behaviors were higher than those of homosexuals. The age of first sexual intercourse ≤14 years old(OR=2.71), 15 to 17 years old(OR=1.87), and 18 to 20 years old (OR=1.35) had a higher proportion of high-risk sexual intercourse than the age of first sexual intercourse of older than 20 years old. In the past year, the proportion of commercial sex(OR=1.80), drug use(OR=4.28), sexually transmitted disease (OR=3.34) diagnosed in the most recent year who had high-risk sexual behaviors were higher. In the pust year, the proportion of stable relationship and cohabitation(OR=0.25), those who had received AIDS prevention propaganda in the most recent year(OR=0.81), and those who knew about AIDS (OR=0.65) were less likely to engage in high-risk sexual behaviors. Conclusion The knowledge rate of HIV/AIDS was low and the incidence of high-risk sexual behavior was high among male college students. Therefore, colleges are encouraged to, actively carry out AIDS prevention and control work, improve the awareness of both HIV/AIDS knowledge and safe sex basics.