Abstract: To learn the rela tionship betw een food structure and dental fluorosis, caries among Xiaerba children in Tibet, we investig ated the Xiaerba and Tibetan children living in Zhangmu town under Mount Qomolangma.The methods of Horowitz' s Tooth surface Index of Fluorosis, caries published by WHO and to tal intake of fluoride published by the WHO/ FAO were used.The results shown that the prevalence of dental fluorosis was lowest among Xiaerba and Tibetan children(37.40% and 25.86%, respectively)in all areas with brick tea type dental fluorosis of China.The caries incidence means of caries in Xiaerba children (28.46%, 0.62)were lower than that of Tibe tan children (62.07 %, 2.17).The change of food structure among children lived in Zhangmu tow n induced decreasing of fluo ride intake and increasing the absorption of much more nutritio n, and enhanced the human abilityag ainst fluorosis.The reason of lower caries prevalence in Xiaerba children may come from stable and rational food strucfure, and higher caries prevalence in Tibe tan children due to much moreconsumption of refined food and sucrose.I f Xiaerba Children cut down appropriately intake of Zanba and milk tea(made from brick tea), it may supply a mode of reducing the harm of fluorosis and caries in prevalence areas of brick tea type fluorosis.