Abstract: Objective To examine the human immunodeficiency virus(HIV)risk behaviors,HIV,hepatitis C virus (HCV),and syphilis infection rates among men who have sex with men(MSM)in Dalian city and to explore the influencing factors of HIV infection among them. Methods A face-to-face questionnaire interview was conducted among MSM recruited with snowball sampling method and the blood samples were collected from the participants for the test fo HIV, syphilis,and HCV. Results A total of 932 MSM were recruited.The prevalence rates of HIV,syphilis,and HCV were 3.42% (32/932),12.12% (113/932),and 1.07% (10/932).In the past 6 months,88.73% (827/932)of the MSM investigated had anal sex with males.Among them,only 52.18% reported consistent condom use during anal intercourse. Multiple logistic regression analyses indicated that lower education background,floating population,commercial sex with men in the past 6 months,and syphilis infection were risk factors of HIV infection.Whereas having HIV test in the last year was a protective factor. Conclusion A high HIV infection rate and high risk behaviors are observed among MSM in Dalian.