In Ertanggou Basin, groundwater is the main water resource of residents' drinking and agriculture irrigation. Study on the hydrochemical characteristics of groundwater can help people understand the underground water chemical environment of renewable ability, scientific and effective management, protection and rational development and utilization of water resources. The spatial distribution pattern of groundwater hydrochemistry in Ertanggou Basin was analyzed using mathematical statistics method, piper diagram method and the Gibbs diagram analysis. The hydrochemical type of surface water is HCO-3—Ca2+, The shallow groundwater in the north basin is replenished by surface water, leaching of sulphate minerals. The hydrochemical type is HCO-3+SO42-—Na++Ca2+, and then go through the dissolved of chlorides and evaporative concentration in the oasis of the South basin plain. The chemical type of groundwater is SO42-+Cl-—Na++Ca2+, the final discharge to Aydingkol Lake and forming the Cl-—Na+ type of water. The surface water quality of north basin is better, and the groundwater has a bad trend. There is a clear rise in the front of the Flame Mountain, and the water quality of the South basin is poor in the Piedmont and around the irrigation area.