Abstract: ObjectiveTo investigate the prevalence and influence factors of HIV/STD among MSM(man who have sex with man)in Shenyang city and afford basis for further interference.MethodsWe investigated MSM in Shenyang by cross research design with anonymous way and collected blood sample to test HIV and syphilis,collected urethral and anus secretion to test chlamydia and gonococcus.ResultsWe collected 231 questionnaires and 229 blood samples of MSM.The infection rate of HIV was 5.67% and that of syphilis was 28.9%.The positive rate of chlamydia from anal swab was 32.8% and that of urethral swab was 1.8%.The gonococcus from anal and urethral swab was undetected.The most young age was ten years old when one's first sex behavior happened.The number of subjects who had one to five male companions in a year was 101 (43.7%).The number of subjects who had six to ten male companions was 54(23.4%).There was 40.57% of MSM who had sex behavior with female at last one year.The rate of condom use was different when their sex behavior happened in stable,chance and commerce sex companion,and the difference was of statistic significance.ConclusionThe HIV and syphilis prevalence of MSM in Shenyang was high.Unsafe sex behavior and other risk factors exist commonly in MSM.So intervention and control of the HIV/STD prevalence in MSM and preventing the infection from MSM to common people is urgently.