Abstract: Abstract This paper presented the results of basic epidemiological investigations on hydatid disease from 1989 to 1991 in Shinaigai Township, Hainan Prefecture of Qinghai. Residents above one year of age were examined for hydatid disease by using ID, IHA, ELISA; the positive rates were 12.1%, 11.1% and 4.6% respectively. Forty three out of 1 611 cases were diagnosed to contract cystic hydatid disease by using B mode ultrasonography, immu nodiagnostic tests and clinical observations, the incidence being 2.7% (adjusted rate 2.8%). Five hundred and nineteen out of 825 (62.9%) sheep and 36 out of 78 (46.2%) yaks were found to be positive in slaughter houses in this area. In addition, 5 641 out of 10 617 (53.1%) livers and 4 527 out of 10 572 (42.8%) lungs of yaks were exhibited to harbour hydatid cyst. Eighteen out of 50 dogs treated with arecoline hydrobromide orally were found to infect with Echinococcus granulosus. Nationality based observation indicated that the prevalence of hydatid disease in Zang nationality was significantly higher than that in Han. The rate of female sheep with hydatid cyst were higher than that of castrated rams. The infection rate of dog in the pasture area was significantly higher than that in town and agricultural area. The above results indicate that Shinaigai is a hyperendemic region of hydatid disease, and design and implementation of appropriate control program is obviously in imperative need.