Objective To evaluate the effect of a health education for preventing HIV/AIDS in floating population. Methods A computerized literature search was carried out in PubMed, CBM (Chinese Biomedical Database), CNKI (Chinese National Knowledge Infrastructure), Wanfang (Chinese) and VIP (Chinese) databases to collect articles published between 1996 and 2006 concerning the effect of a HIV/AIDS education intervention in floating population. We also checked the reference lists of relevant articles. The study type was self-control intervention study. Meta-analyses were performed to assess 3 outcomes of the intervention, i.e. knowledge about HIV transmission, means of prevention and attitudes towards HIV/AIDS patients. Fixed and random effect models were employed to combine results after a heterogeneity test, with rate difference (RD) used as the indicator of intervention effect. Results The analysis showed that the RD for knowing the sexual transmission route of HIV, the RD for knowing the effect of condoms for HIV prevention, and the RD for changing attitudes towards HIV/AIDS patients, i.e. treating them as ordinary people, were increased by 16% (0.10, 0.22), 22% (0.17, 0.28) and 19% (0.13, 0.25), respectively. Conclusion Health education for preventing HIV/AIDS is effective in changing knowledge and attitudes in floating population.