Abstract: Objective To examine the prevalence and related factors of human immunodeficiency virus(HIV)infection among men who have sex with men(MSM)in Chaoyang city in 2012 and to provide evidences for developing control measures.Methods The MSM were recruited through the referrals of a mercy working team for AIDS control and a questionnaire survey and laboratory test were carried out in the participants.The data collected were processed with Epi Data 3.1 and analyzed with SPSS 17.0.Results Among the 475 participants,122(25.7%)had HIV antibody test,of which,120(98.4%)knew the test results.For the participants with eligible respondence,the median age of first sexual behavior was 21.5 years;during the previous six months,the median number of sexual partners of the MSM was 5;47(9.9%) had commercial sex behavior and 35(7.4%) had commercial homosexual behavior;147(31.0%) had sex with women.Of all the participants,29(6.1%) had syphilis infection;12(2.5%)were positive for HIV;and 2(0.4%)suffered from both syphilis and HIV infection.Conclusion The most of the MSM in Chaoyang city have high-risk sexual behavior and HIV prevalence is rising due to unsafe sex behavior with multiple sexual partners.