By the field investigation on BaYinTaohai of WuHai,this article found that ,although this town locates in the northwest arid areas with little rain and big evaporation, the groundwater is abundant. Many artesian wells and springs are founded in this place. Through the analysis of the isotope characteristics of the groundwater in the study area, It is concluded that the shallow groundwater of south Wuhai recharge from local precipitation,while deep confined water recharge from allogenic water with isotope dilution.