Abstract: Objective To explore the awareness and high risk bebavior of HIV/AIDS and the prevalences of human immunodefficiency virus(HIV),syphilis,hepatitis C among sex workers of different nationdlities in frontier trade area in order to provide basis for intervention of the diseases. Methods A questionnaire survey was carried out based on the scheme of National HIV Comprehensive Sentinel Site Surveillance.Serum samples were tested for HIV,syphilis,and hepatitis C. Results Totally 262 sex workers took part in the survey and 244 blood samples were collected.Among 177 Chinese sex workers,the average age was 33 years,mainly ranging from 20 to 45 years old,and most of them were married (65.54%)and from other provinces(61.58%).The education level of the sex workers was mainly junior school or lower. For the 85 Vietnamese sex workers,the average age was 25 years old and 64.71%of them were younger than 24 years old and 62.35%of them were single with the education level of junior school or higher.The rate of correct answers to 6 items in the questionnaire was 99.62%and the rate of "mosquito bite could not transmit HIV" was very low.Condom use rates among Chinese sex workers in the last sex a and last month were lower than those of among Vietnamese sex workers with significant differences(χ²=20.24,P<0.01;χ²=32.44,P<0.01).Of the Chinses sex workers,3.39%used durg.The infection rates of HIV,syphilis,and hepatitis C were 0.41%,1.64%,and 0.82%,respectively. Conclusion The rate of correct answer to "mosquito bite could not transmit HIV" is very low among the sex workers.Condom use rate among Chinese sex worders is low.There were drug users and HIV,syphilis,hepatitis C infections among Chinese sex workers.