Objective To understand the epidemic situation of hydatid disease in Gansu Tibetan Autonomous Prefecture(Gannan state) Gannan Province,and prevalence of the disease in population,livestock and final host dogs,and to evaluate the effectiveness of prevention and control measures.Methods In 2012:①An investigation was carried out according to the requirements of Technical Solutions of Hydatid Disease Prevalence,Gansu Province; in every county(city) of Gannan Prefecture,administrative villages were selected as survey units,by stratified cluster sampling based on the semi agricultural semi pastoral areas,pastoral areas,agricultural areas and towns.According to the proportion of the population of each layer to the population of each county,the number of people and the number of villages to be surveyed were determined.Sixteen villages were selected,and 200 people were selected in each village(from a neighboring village to make up the insufficient number in case of need),and B ultrasound method was used to carry out the census.②Children serum survey:stratification was done according to pastoral areas,semi agricultural semi pastoral areas,agricultural areas and towns population in each county(city),1 primary school was selected,children less than 12 years old were examined by B Ultrasound,and serum antibodies of Echinococcus granulosus were tested by enzyme-linked immunosorbent assay(ELISA).③ Surveillance of source of infection:in the selected villages,20 kennel households were selected in each village,dog feces was collected,and canine Echinococcus antigen was detected by double antibody sandwich ELISA method.④)Monitoring of intermediate host:1 000 sheep (or 500 cattle) were selected in each county(city),and hydatid disease was examined by anatomical method.⑤Investigation of health education was done in the form of a questionnaire survey of hydatid disease prevention knowledge and behavior survey on the awareness rate.Results The prevalence rate of population was 0.10％ (29/28 960); prevalence rate of herdsmen was 0.13％ (17/13 015); farmers prevalence rate was 0.06％(8/12 780); in children under 12 years of age,the infection rate was 2.64％ (336/12 728) ; dog infection rate were 3.90％ (117/3 001) ; livestock infection rate was 1.72％ (121/7 027); and the infection rates of cattle and sheep were 2.41％(38/1 574) and 1.52％(83/5 453),respectively.The rate increased from 40％(720/1 800) to 70％(1 260/1 800) of hydatid disease prevention knowledge awareness in farmers and herdsmen after health education.Conclusions The scope of hydatid disease in Gannan Prefecture is broad; the patient population mainly is herdsmen,and farmer is second.Epidemic factors include contact canine and vices; the farmers and herdsmen have low awareness of hydatid disease prevention knowledge.Poor production and lifestyle are difficult to change in the short term,we need to further strengthen the prevention measures.