Abstract: Objective To understand the prevalence of acquired immunodeficiency syndrome (AIDS) and the influencing factors among men who have sex with men (MSM) in Wenzhou, Zhejiang province, and provide scientific evidence for effective AIDS prevention and control. Methods The survey subjects were recruited through snow ball protocol, field visit and web based registering from 2011 to 2013,unified questionnaire was used in the survey and blood samples were taken from the subjects for HIV and syphilis antibody detection. Descriptive epidemiological analysis was conducted on the subjects' demographic characteristics, AIDS related knowledge awareness and risk behaviors. Chi-squared test and multivariate logistic regression analysis were performed on the difference in HIV infection in subjects with different demographic characteristics. Results From 2011 to 2013,1204 MSM were surveyed. The majority of the MSM were found in parks/public toilets, accounted for 28.9%. The average age of the MSM was (30.168.64) years and the MSM aged30 years accounted for 53.8%, the unmarried accounted for 59.7%, and the MSM with education level of high school accounted for 59.8%. Up to 62.4% of MSM had local residence for more than 2 years. The AIDS related knowledge awareness increased with year (2=80.23, P0.05).The rate of homosexual behavior among MSM was 75.7% during the past six months. The condom use rates at each homosexual behavior during the past six months and at latest homosexual behavior were 47.1% and 75.7% respectively, no annual differences were observed (2=3.81 and 0.06, P0.05). The rate of commercial homosexual behavior during the past six months declined with year (2=73.69,P0.05), but there were no annual differences in the rate of condom use at each homosexual behavior (2=7.82,P0.05). The positive rate of HIV antibody was 7.39%, the difference in annual positive rate had no statistical significance (2=3.63,P0.050). Multivariate logistic regression analysis showed that the HIV infection rate of MSM was associated with sample source, local residence time, syphilis prevalence. Conclusion The positive rate of HIV antibody among MSM is high in Wenzhou. knowledge-practice inconsistent phenomenon is obvious, it is necessary to strengthen the comprehensive intervention among MSM.