Objective To study the preventive effects of fluoride drop on dental caries for children.Methods The compara- tive method was carried out in 1 200 children aged from 3 to 4 .The subjectswere divided into three groups: fluoride drop group, fluoride toothpaste group and control group. The research period was 2 years.Results The results demonstrated that new dfswas 1.35±0.57 in the fluoride drop group after one year, 1.85±0.57 after two years. The new dfs was 1.53±1.09 in the fluoride toothpaste group after one year and 2.75±1.33 after two years. There was no significant difference of the dfs reduction between fluoride drop and toothpaste group.Conclusion Fluoride drop is effective in the prevention of dental caries in Chinese kinder- garten and primary school children.