Objective: To examine the prevalences of sexually transmitted disease and HIV,and sex behavior among female sex workers as well as the risk factors associated with the treponema pallidum (TP) and chlamydia trachomatis (CT) infections in Jiangsu province. Methods: The subjects were recruited by convenient sampling. Demographic and behavioral information was obtained using face-to-face questionnaire interview. Blood sample and cervical swab were collected for the tests of TP,HIV,CT and neisseria gonorrhoeae(NG). Data analyses were performed using SPSS13.0. Results: A total of 1 806 subjects were recruited with questionnaire information,and blood samples were collected. The median age was 25 years old. The prevalences of TP,CT,NG and HIV were 8.4%,14.7%,5.4% and 0.3% respectively. Risk factors for TP included lower education level and working in the lower class venues. Risk factors for CT included being younger,higher education level,having unprotected sex with clients during the past month. Conclusion: High STD prevalence and widespread risk behaviors are identified among female sex workers in Jiangsu province. Targeted intervention should focus on those working female sex workers.