Abstract: Objective The present investigation was conducted to analyze the sexual behaviors among men who have sex with men (MSM) in Shaoxing City, so as to provide some information for prevention and control of the risks in this population. Methods MSM were recruited snowball sampling and face- to- face interviews were carried out. 5ml venous blood was collected from each subject for HIV and Treponema pallidum antibodies. Results 55 MSM were included in this investigation, of whom the mean age was 26.03 4.22. The study revealed that the 55 MSM experienced the first sex at the age of 20.152.36, during which 72.73% of the partners were men.87.27% of them have had sex with men in the recent 6 months, and each of them have an average of 2.21 partners. During the anal sex activities in the last 6 months, only 40.0% of the MSM used the condoms each time. Conclusion The unprotected sexual behaviors are prevalent among the MSM in Shaoxing City, which is posing a potential widespread of HIV/AIDS. Effective measures need to betaken immediately to get this risky situation under control.