ObjectiveTo analyze the epidemic situation and risk factors of AIDS in 404 men who have sex with men (MSM) in Chongqing district, and provide a scientific basis for AIDS prevention and control.MethodsInvestigation was conducted by questionnaires,  the targets were surveyed by HIV screening and diagnosis test, and AIDS infection rates were calculated. ResultsAmong 404 MSM who have multisexual partners and the behaviors of unprotected sexual penetration, AIDS infection rate was 15.10%. The age of initial sexual behavior （χ2=16.61，P=0.001）, education background （χ2=28.68，P=0.000）and condom use frequency during sex behavior with female in the last six months （χ2=7.57，P=0.02） were different respectively, HIV infection rate was significantly different respectively.ConclusionThere is a high prevalence of HIV infection among MSM, effective measures to control AIDS in the MSM should be taken.