Abstract: Objective To understand the prevalence of high risk behaviors and infection status of HIV among men having sex with men (MSM) in Guangzhou and provide scientific evidence for developing effective intervention measure. Methods The analysis was conducted on the data obtaining from anonymous questionnaire survey in MSM and from HIV and syphilis detections among them. Results The average age of MSM surveyed in Guangzhou was 27 years, and half of them (51.64%) were aged 20 to 30 years. The average age when they had the first homosexual activity was 23 years. Among MSM aged30 years, 81.95% (436/532) had got married. Totally 41.72% (567/1359) of MSM had multi sexual partners in the latest 3 months，only 67.05% (1058/1578) used condemn in the latest sex with men and 55.16% (844/1530) used condemn in all sex with men in the latest 3 months. The infection rate of HIV was 5.20% (83/1596), and the infection rate of syphilis was 6.95% (111/1596).The condemn use rate in MSM with passive anal sex was significantly lower than that in those with active anal sex. Having active anal sex, having both active and passive anal sex and low education level were the risk factors to have homosexual activity with multi partners Having passive anal sex and homosexual experience for less than 5 years were the risk factors to have unprotected anal sex with men. Syphilis infection, education level and role in homosexual activity were the risk factors for HIV infection. Education level, having multi sexual partners and age were the risk factors for syphilis infection. Conclusion The AIDS epidemic is serious and the prevalence of high risk behaviors of having sex with multi partners and unprotected anal sex are high among the MSM in Guangzhou. It is urgent to conduct intervention in MSM to reduce their high risk behaviors.