Objective To understand the prevalence of HIV infection,syphilis and hepatitis C and related behavioral factors in female sex workers (FSWs) and other 6 risk populations in Tibet Autonomous Region.Methods A cross-sectional survey was conducted among 2 000 FSWs,200 men who have sex with men (MSM),200 drug users,1 200 male migrants,5 600 young students,as well as hospital patients and pregnant women in Lhasa,Qamdo,Nyingchi,Xigaze Shannan,Ali and Nagqum from June to December 2015.Face to face interviews were conducted to collect their demographic and behavioral information,and blood samples were collected for the tests of HIV,syphilis and hepatitis C virus (HCV) antibodies.The enumeration data were described by using rate and constituent.Results A total of 20 597 participants were involved in cross-sectional survey.The positive rates of HIV and syphilis antibodies were 5.81％(124/2 133) and 0.05％ (1/2 133) respectively among FSWs.The positive rates of HIV and syphilis antibodies were the same (9.80％,10/102) among MSM.There were no HIV infection detected in among drug users,male migrants and young students,but the positive rates of syphilis antibody were 4.00％(4/100),0.33％ (4/1 297) and 0.08％ (4/5 095)respectively.The positive rates of HIV and syphilis antibodies were 0.04％(2/5 565) and 1.64％(91/5565) among hospital patients.The positive rates of HIV and syphilis antibodies were 0.11％(7/6 305)and 1.19％(75/6 305)among pregnant women.The positive rates of HCV antibody were 1.00％ (1/100)among drug users and less than 0.50％ in other risk populations.The overall consistent condom use rate was low.Conclusions In Tibet,HIV infection mainly occurred in the MSM,syphilis mainly occurred in FSWs and MSM,HCV infection mainly occurred in drug users.The AIDS related knowledge awareness rate was low in these risk populations,and less of them received intervention service.