ObjectiveTo investigate the prevalence of syphilis among outpatients in sexually transmitted disease (STD) clinics in Guangxi Zhnang Autonomous Region,and to assess the socioeconomic and behavioral factors associated with the infection.MethodsThe outpatients to 14 STD clinics in 8 cities of Guangxi Zhnang Autonomous Region were investigated with questionnaires by their doctors at the first visit.Venous blood samples were obtained from these outpatients and subjected to toludine red unheated serum test (TRUST) to screen for syphilis.Treponema pollidum particle agglutination (TPPA) was performed for TRUSTpositive samples.The epidemiological data were collected by using EpiData software,statistically analyzed by using SPSS13.0 software package.ResultsA total of 10 930 STD outpatients were recruited in the study,and 1297 samples were confirmed to be both TRUST and TPPA positive.The prevalence of syphilis was 11.9％ in all of the outpatients,14.3％ in female outpatients and 10.3％ in male outpatients,13.3％ in the outpatients of Zhuang nationality,and 11.4％ in those of Han nationalily.Multivariate analysis showed that syphilis was independently related to female sex[odds ratio(OR) 2.23,95％ confidence interval(CI) 1.69 - 3.00,P＜0.01 ],low educaiion level (middle school:OR 1.70,95％ CI 1.11 - 2.62,P ＜ 0.05; primary school or illiteracy,OR 1.98,95％ CI 1.13 - 3.46,P＜0.05),annual income of more than 30000 Yuan (OR 1.91,95％ CI 1.18 -3.10,P ＜ 0.01 ),commercial sex workers or having multiple sexual partners(OR 1.54,95％ CI 1.16 - 2.06,P ＜0.01 ).ConclusionsSyphilis serology should be the routine test in STD clinical settings in Guangxi region,and the intervention should be enhanced to control the prevalence of syphilis in high-risk populations.