Abstract: ObjectiveTo understand the knowledge of contraception for AIDS prevention and to explore its influence factors among the migrants in Shanghai city for making in tervention.MethodsOverall 2001 migrants from Minhang district of Shanghai city were investigated with a self compiled questionnaire.ResultsFor the question whether the contraceptive method canprevent AIDS virus infection,the average score was 39.57±31.77.The ratios of correct answer about contraceptive method among the migrants were 76.06% for condom,38.63% for coitus interrupt,33.38% for female condom, 21.64% for vaginal sponge/diaphragm/cervical cap,37.03% for vasectomy,and 32.69% for intrauterine device with in domethacin,respectively.The single factor analysis demonstrated that the influencing factors of knowledge of contraception for AIDS prevention were age(χ²=11.15,P<0.01),marital status(χ²=57.12,P<0.01),education background (χ²=19.37,P<0.01),workplace(χ²=31.36,P<0.01),average individual monthly income in 2007(χ²=10.86, P<0.01),and registered permanent residence(χ²=19.88,P<0.01).Multi factor analysis showed tha tage,marital status, education background,workplace,and average monthly income of individual and family in 2007 were related factors.ConclusionThere are differences in knowledge of contraception for AIDS prevention among different floating population.