Abstract: Objective　To assess the dental caries prevalence of children in Yinchuan.Methods　The 3-, 5-, 12-, 15-year- old children were chosed from nursery, primary and middle schools of Yinchuan in 1990, 1996 and 2001. The surveywas carried out by five senior dentists from stomatologic hospital of Yinchuan according WHO criteria. DMFT, DMFS and the ratio of tooth filled were counted.Results　From 1990 to 2001, the prevalence of dental caries of 3-, 5-, 12-year-old children was degression (P<0·01). Butthe prevalence of dental caries of 15-year-old children had no obvious change. The dental caries of small propor- tion of children were serious. The ratio of tooth filling was low.Conclusion　With the development of oral health education, the prevalence of dental caries of 3-, 5-, 12-year-old children in Yinchuan is descend. But the diagnosis, prevention and treatment should be strengthened, and the ratio of tooth filling should be increased.

Key words: dental caries, prevalence, epidemiology