Objective To grasp the prevalence of drinking brick-tea type fluorosis in Tibet,and to provide scientific basis for the development of prevention and control strategies.Methods Twelve counties were selected from 7 regions in Tibet.In accordance with the "Drinking Brick-Tea Type Endemic Fluorosis Monitoring Program",a total of 46 administrative villages were selected as survey points using the cluster stratified sampling method.Household water samples,tea-water samples and adult urine samples were collected,and household fluorine intake status and incidence of skeletal fluorosis in adults over 16 years old were investigated.In the rural grade primary school where the village children were concentrated,all children aged 8-12 were selected,urine samples were collected,and the prevalence of dental fluorosis was investigated.Fluoride contents in tea,water,and urine were detected by ion selective electrode method.The dental fluorosis and skeletal fluorosis were examined and judged according to the "Diagnosis of Dental Fluorosis" (WS/T 208-2011) and the "Diagnostic Criteria for Endemic Skeletal Fluorosis" (WS 192-2008),respectively.Results A total of 46 villages in 12 counties were investigated,1 992 of water samples,1 662 of tea samples,664 of children urine samples,3 186 of adult urine samples were detected;547 children aged 8-12 were examined dental fluorosis and 3 196 adults were examinea skeletal fluorosis,respectively.The water fluoride contents in all the investigated villages were less than 1.0 mg/L;the average fluoride content in brick-tea water was 6.12 mg/L,within the range of 0.11-84.00 mg/L,and the average daily brick tea fluorine intake of residents was 24.98 mg.The geometric mean of urine fluoride in children and adults was 0.76,2.28 mg/L,respectively.The prevalence rates of dental fluorosis in children and skeletal fluorosis in adults over 16 years old were 31.81％ (174/547) and 48.59％ (1 553/3 196),respectively.The children dental fluorosis index was 0.60.The detection rate of skeletal fluorosis in adults aged 36-45 was 13.37％ (69/516).Conclusions The prevalence of drinking brick-tea type fluorosis in Tibet is serious and widely distributed.In particular,the prevalence rate of skeletal fluorosis in adults is relatively high,while that of dental fluorosis in children is relatively mild.The prevention and control of drinking brick-tea type fluorosis in Tibet brook no delay.