Abstract: Objective To understand the characteristics of HIV/AIDS related high-risk behaviors among men having sex with men (MSM) in Guilin and provide basis for the effective intervention and prevention. Methods A anonymous and face to face questionnaire survey was conducted among 315 MSM in the setting where MSM liked to go in the urban area of Guilin, and blood sample were taken from them for HIV, syphilis and HCV test. Results A total of 315 MSM were interviewed and tested, their average age was 28.288.6 years. The awareness rate of AIDS-related knowledge was 30.16%. In these people,65.08% had unprotected anal intercourse with male partners in the past six months with average sexual partners number of 3.161.56 (the highest number was 22),6.31% paid for homosexual service and 3.07% provided homosexual service for money. The rate of condom use was 15.12% in the past six months. 18.10% of MSM had sex with women,but the condom use rate was only 1.79%. The infection rate was 1.59% for HIV (5 cases),2.54% for syphilis (8 cases) and 0.32% for HCV (1 case). Conclusion Due to the high prevalence of high risk behaviors, the infection rate of HIV/STD among MSM was high and their awareness rate of AIDS knowledge was low in Guilin. It is urgent to conduct effective intervention to control the epidemic of AIDS in this population. This study was funded by Research Project of AIDS with the 4th Round Global Fund in Guangxi