The purpose of this study was to assess trends in the HIV epidemic and risk factors for HIV infection among men having sex with men (MSM) in mainland China. A literature review was conducted. Data from studies regarding HIV prevalence, syphilis infection and risk behavior, were pooled into three chronological stages. The independent correlates of HIV infection were gathered in order to guide the development of future interventions. HIV prevalences were 2.5% (95%CI 1.8-3.7), 1.8% (95%CI 1.1-2.9) and 3.3% (95%CI 2.0-5.3) before 2004, during 2004 to 2005 and 2006 to 2007, respectively. About two-thirds of MSM had multiple male sex partners during the previous six months (P6M), and more than one third of MSM engaged in unprotected anal intercourse (UAI) during last sex. Only UAI among commercial sex workers declined significantly. More than one quarter of MSM had female partners in P6M and the proportion having multiple female partners declined. The rates of unprotected vaginal sex had a downward trend. The prevalence of injecting drug use was low and remained the same. The number of lifetime male sexual partners and the frequency of anal sex in P6M were independently associated with HIV infection; UAI was correlated to the number of male partners, buying sex from males, being part of a mobile population, prior HIV testing and having a prior sexually transmitted disease (STD). We conclude intervention programs targeting UAI and multiple partners are urgently needed to control the HIV epidemic among MSM in mainland China.