Background Men who have sex with men (MSM) have been impacted by HIV and now as an important driver of the HIV/AIDS epidemic in China.This study collected HIV sentinel surveillance system data on the MSM population to describe the characteristics and trends of the HIV epidemic among MSM in China from 2003 to 2011.Methods Data on HIV prevalence and risk behaviors from 2003 to 2011 were obtained from the national HIV sentinel surveillance database.Results MSM sentinel surveillance data for 2011 showed that proportions of MSM who consistently used condoms during anal sex in the last six months and at last anal sex encounter were 43.3％ and 74.1％,respectively.Between 2005 and 2011 there were no significant changes in the proportion of consistent condom use.The proportion of MSM who had multiple male sex partners in the last six months increased.Overall HIV prevalence over the years showed a rising trend from 0.9％ in 2003 to 6.3％ in 2011.The syphilis antibody positive rate was 7.8％ in 2011.In addition,the proportion of MSM in heterosexual marriages was rising,AIDS awareness was also increasing,and the proportion of MSM who had taken an HIV test in the last year and was aware of the results rose.The proportion who had received intervention services in the last year stabilized.Conclusions HIV prevalence in MSM populations is rapidly and widely distributed.MSM who are in heterosexual marriages may be a bridge group transmitting HIV to their heterosexual partners.The risky sexual behavior among MSM will remain a serious and important driver of China's AIDS epidemic over the next period of time.Intervention need to be strengthened,as does the effective implementation of measures to control AIDS and prevent it from spreading further.