Abstract: Objective To clarify the distribution of caries in the first permanent molars of primary school students in Xuzhou, and make analyis to provide reference for oral health care for primary school students.Methods This study adopted the method of crosssectional study.According to the 4th edition of dental health investigation standards of WHO, 3018 primary school students in downtown areas of Xuzhou were surveyed, which included 1565 males and 1453 females.The result was statistically analyzed by SPSS 16.0.Results The total caries prevalence rate of the first permanent molars was 15.11%.The average decayedmissingfilled(DMFT) teeth were 0.283.The permanent caries prevalence increased obviously with age.The caries prevalence of girls was 17.48%, which was higher than that of boys(12.91%), and there was statistically significant difference (P<0.01).The caries prevalence of the first permanent molars in the mandibles were higher than that in the maxillaries.The total caries filling rate was 7.25%.Conclusions The caries prevalence of the first permanent molars in primary school students is high, while the filling rate is low in Xuzhou.Some measures should be taken to prevent and treat caries.