This article reports on the result of an investigation on the prevalence of liver alveolar echinococcosis (LAE) and liver cystic echinococcosis (LCE) in the peasants and the residents of Xiji County, Ningxia Hui Autonomous Region. Among 2,389 selected persons examined with B-ultrasound, 197 cases were diagnosed to have LAE or LCE; the prevalence being 8.2%. Of the 197 cases, 141 (5.9%) had LAE; 56 (2.3%) had LCE. Among 1,413 peasants, 9.7% had LAE; 3.8% had LCE. Among 976 residents, 0.4% had LAE, 0.2% had LCE. Obviously, the peasants were more prone to be infected with the disease, suggesting LAE had much to do with the job of hunting the fox and capturing the Citellus dauricus, while the infectious source of LCE was mainly the domestic dog.