Abstract: Objective To understand AIDS and STD knowledge,attitudes and behaviors of floating population of Li Minority in Hainan Province.Methods An interviewer administered questionnaire was used to collect basic data of AIDS and STD including demographic information,attitudes and behaviors of the floating population of Li minorities investigated.Results A total of 251 subjects were interviewed,among whom 133 were Li Minorities.173 had ever heard of A IDS,accounting for 82.92%,64.14% of whom getting AIDS knowledge from television.The correct answer rate to STDA IDS konwledge ranged from 24.10 to 80.08 percent.64.54% of them were worry about being infected by HIV through injection by doctors,and 83.67 percent would go to hospital examine and treat AIDS if being infected.The condom use rate was 39.84%,among which 30.93% were insisted to use by themselves.4 syphilis infections were found,accounting for 1.59%,but no HIV infection.Conclusion The floating population of Li Minority are lack of knowledge of AIDS and STD prevention,so it is imperative to develop wide education of AIDS and STD in them.