Abstract: Objective To evaluate the relationship betweent the knowledge level related to HIV/AIDS and high-risk sexual behaviors among men who have sex with men,to provid proof for HIV/AIDS prevention and control in the future.Methods A cross-sectional anonymous questionnaires survey was carried out by trained shopkeepers and waiters among MSM who visited gay bars.Results Among 174 participants,their knowledge,level about HIV transmission routes was better than the basic HIV/AIDS knowledge,the rate of correct related to HIV transmission routes was 78.1%～98.9%,and the basic HIV/AIDS knowledge only was 12.6%～67.8%,The main sources which they obtained the HIV/AIDS knowlege,were newspaper,magazine,website,television and broadcast.The score of HIV transmission routes was significantly better among those who frequen "thomosexuality" websites.Age was from 25 to 30 years,sexual orientation was homosexuality,and live the city more than 6 months than those who non-frequen "thomosexuality" websites,age was yonger than 25 years or older than 31 years,sexual orientation was non-homesexuality,and live the city less than 6 months(P<0.05).The score of basic HIV/AIDS knowledge was singnificantly higher among those who frequent "homosexuality" websites than who non-frequent "homosexuality" websites(P<0.05).It was not significant difference for the score of basic HIV/AIDS knowledge and HIV transmission routes which distributed among high-risk sexual behavior and multi-sexual partners.Conclusion The knowledge level related to HIV/AIDS was lower,which was not associated with the high-risk sexual behaviors and multi-sexual partners among MSM.