As the largest inland river basin and one of the arid zones of NW China,the Tarim River Basin (TRB) is the most important production base for grain,cotton and high-quality fruits in China,with abundant natural resources but fragile eco-environment.Groundwater is not only an important source of public water supply but also important to the regional ecology in this area.Despite the importance of groundwater in TRB,very little is currently known regarding the temporal and spatial variation,controlling factors and solute sources of groundwater for the entire basin.