Objective To understand the state of AIDS knowledge of the students in the migrant workers’ children school in Nanjing, in order to provide foundation for the further health education. Methods To design the questionnaire about AIDS knowledge, and investigating all the 5 ~ 6-grade students in the migrant workers’ children school in Jianye District of Nanjing, at the same time, to select an ordinary city primary schools in Nanjing for comparison. Results 93.8% of the migrant workers’ children have heard about AIDS, 93.4% of them would like to know the AIDS knowledge, 89.8% of them think that the AIDS education is very important. Their awareness rates of non-AIDS routes of transmission and preventive ways are mostly lower than 70%, and they do not grasp AIDS knowledge as good as the ordinary primary school students. Conclusion The AIDS knowledge known among the children of migrant workers is poorer, it is important to reinforce the health education in the students.