Abstract: ObjectiveTo know the status of HIV and syphilis infection,HIV/AIDS knowledge and condom use among young men who have sex with men(MSM).MethodsOverall 150 young MSM were recuited in Beijing,Harbin, Zheng zhou and Chengdu,respectively,with snow balling sampling.The participants were investigated with a questionnaire on demographics,HIV/AIDS related knowledge,sexual bebavior and condomuse a swell as HIV and syphilis testing.ResultsAmong the participants,the prevalence of HIV infection,syphilis infection and concurrent infection of HIVand syphilis was 6.7%,8.3%,and 1.5%,respectively.The prevalence of HIV infection was 4.5% in young MSM with insertive anal sex, 6.3% in young MSM with receptive andal sex,and 8.1% in the MSM with versatile anal sex,and the prevalence of syphilis infection was 11.2%,10.2%,and 7.8% accordingly.There was no signifecant difference in HIV/AIDS knowledge,condomuse and prevalence of HIV infection between different anal sex players(P<0.05).In the previous 6 months,the rates of self report of unprotected insertive,recptive,oral, and vaginal intercourse were 52.5%,45.0%,87.5%,and 22.5% in HIV positive participants,and 31.1%,37.7%,72.9%,and 14.3% in negative participants.ConclusionThe rates of HIV and syphilis are high among young MSM in cities of China.The risk of HIV infection is common among young MSM with receptive or insertiveanal in tercourse.