Abstract: Objective To identify the levels of AIDS knowledge and behavior among county town residents.Methods Using clustered sampling method,1 654 residents were recruited and interviewed in the eight AIDS project counties in Anhui province.A structured questionnaire was anonymously administered face-to-face for each participant.Results Among 1 614 residents,the proportion of knowing A IDS facts was 84.3%.The awareness rates of HIV transmission and non-transmission routes was 93.5% and 82.6% respectively(χ²=325.94;P<0.001).The proportion of knowing voluntary counseling and test(VCT)service was 76.5% and the rate of using VCT service was only 17.5%.The proportion of knowing basic facts about voluntary blood donation was 55.7%.The proportion of having extra-marital sex was 3.6% among mobile people and 36.7% of them use condoms with casual partners.Conclusion County town residents in Anhui AIDS project areas had a high level of AIDS knowledge,but their knowledge was not comprehensive,and lack of knowledge about voluntary blood donation and VCT.Extra-marital sex existed and condom use rate was low among floating population.Comprehensive educational and interventional measures should be taken to increase AIDS(including blood donation and VCT) knowledge and promote safe sex and condom use among floating population in county town.