Abstract: Objective To examine high risk behaviors and infection of human immunodeficiency virus(HIV) among men who have sex with men(MSM) in Guangzhou and to provide evidence for making effective intervention measures.Methods With cooperation of non-governmental organizations and network mobilization,a questionnaire survey and serological test were conducted among MSM taking voluntary consultation for AIDS/HIV infection.Results Totally 1 472 MSM with the average age of 28 years were surveyed.Among the MSM,40.70%(591/1 452) had 2 or more sexual partners during the previous 3 months and 69.16%(1 018/1 472) used condom when having every homosexual sex during the previous 1 month and 55.67%(712/1 279) during the previous 3 months.The infection rate of HIV and syphilis were 5.98%(88/1 472) and 4.08%(60/1 472) among the MSM.The receptive MSM had their first anal sex at younger age and had relative less number of sexual partners.The receptive MSM and the MSM with both receptive and insertive anal sex showed significantly lower rate of condom use and higher rate of HIV infection compared to insertive MSM.Conclusion The MSM in Guangzhou city had high prevalences of HIV infection,unsafe sexual behavior,and lower rate of condom use,and were the population at high risk of AIDS transmission with less self-protection.