Abstract: Objective To understand the epidemiological characteristics of HIV positive men having sex with men (MSM) in Hangzhou and provide scientific evidences for the prevention and control of AIDS. Methods The retrospective analysis was conducted on the epidemiological characteristics of HIV infection cases in MSM from 2004 to 2010. Blood specimens were taken from the cases recruited in follow up from April to June 2011 to detect antibodies to syphilis. Results By 2010,totally 581 HIV infection cases in MSM had been reported in Hangzhou since 2004 when the first case in MEM was reported, which accounted for 33.8% of the total HIV infection cases. The cases were mainly distributed in age group 20-39 years, accounting for 79.5%. The cases in married men accounted for 22.7% and increased with age. The median of homosexual partner number of MSM was 7, and 7.4% of the HIV infected MSM had heterosexual partners, 36.5% had STD history. The prevalence of syphilis was 24.6%. Conclusion MSM was the high risk population for HIV infection and also the population which would spread HIV in general population in Hangzhou, so it is quite urgent to take measures to reduce the HIV infection in this population.