Abstract: Objective To understand the awareness of AIDS related knowledge and the prevalence of related risk behavior among female sex workers (FSWs), and evaluate the effect of AIDS intervention among them. Methods After the conduction of AIDS intervention among FSWs in Guilin in 2007, 2 questionnaire surveys of AIDS related knowledge awareness and 2 serological detections were conducted among 300 FSWs selected by random sampling in 50 recreation centers with different grades in December 2009 and in June 2010 respectively and between the 2 surveys, the regular and constant outreach intervention was conducted among them. Results The 2 surveys indicated that the awareness rate of key AIDS related knowledge was 93.7% and 94.3% respectively among the FSWs, the difference on the awareness rate was not statistically significant (2=0.12, P＞0.05). The condom use rates at the latest commercial sex and at the commercial sex in recent month was higher in 2010 than those in 2009, the difference was statistical significance (2=26.844,P＜0.05,2=25.227,P＜0.05). Conclusion The outreach intervention conducted among FSWs was effective to help them to reduce risk behavior, but it is essential to conduct intervention constantly among FSWs because they belong to floating population.