Abstract: Objective To understand the HIV infection status and associated risk factors among men who have sex with men (MSM) in Hangzhou, Zhejiang province, and provide evidence for effective HIV prevention and control. Methods Face to face questionnaire survey was conducted among the MSM recruited by snowballing method in the communities in Hangzhou from 2009 to 2014. Blood specimens were collected from them for the detection of HIV and syphilis antibodies. Results A total of 2892 MSM were enrolled in the study. The HIV infection rate was 7.75% in 2009 and 13.10% in 2014, which showed a statistically significant increase (Z=3.610,P=0.0003). The overall awareness rate of AIDS related knowledge was 92.53%. The results of multivariate logistic regression analysis showed that the educational level ofOR=1.903, 95% CI:1.471-2.462), anal sex with homosexual partners (OR=1.838, 95% CI:1.263-2.676), sexually transmitted disease (OR=1.572, 95% CI:1.057-2.336), syphilis (OR=2.802, 95% CI:2.055-3.819) were the independent risk factors for HIV infection. Conclusion The positive rate of HIV had reached a high level among MSM in Hangzhou. Although the MSM had high awareness of AIDS related knowledge, high risk sex behaviors were still common. It is necessary to conducted effective intervention among MSM to prevent HIV transmission.