【Objective】 To investigate the prevalence of endemic fluorosis in Hancheng district, and to provide scientific basis for the prevention and cure of endemic fluorosis in fulture. 【Methods】 The fluoride content in drinking-water was determined by the fluoride selective ion electrode in the ruins of an ancient city in Hancheng district. The dental teeth of children aged 8～12 years at school was examined with Dean's index The fluoride content in drinking water was detected with F-ion selective electrode. 【Results】 The dental fluorosis of 457 children aged 8～12 years in 11 villages in Hancheng district were examined the total detectable was 177. The detectable rate of dental fluorosis of children aged 8～12 years was 16.4 %, tiny patients 57(the prevalence rate was 12.2%), light patients 18 (the prevalence rate was 3.9 %). No moderate and severe patients were oberserved. 【Conclusions】 The total detectable rate of children dental fluorosis in Hancheng district is 16.4%, in order to maintain prefect ancient relics in Hancheng district, meanwhile, to improve the present situation of manage and usage for the well of control fluorosis. The most efficient method to deal with a situation preventing drinking water fluorosis is altering water source in order that advance the work of control fluorosis.