Abstract: The Ordos Basin is a large-scale tectonic sedimentary basin in the northwestern China.Lower Paleozoic carbonates,Upper Plaeozoic-mesozoic clastic rocks,and quarternary sediments occur on the basement of Precambrian metamorphic rocks in this area with a total thickness of 6,000 m.The aquifer system in the Ordos Basin was divided into the peripheral Cambrian-Ordovician karst system,the Cretaceous clastic rock fracture-pore aquifer system,the eastern basement rock fractured aquifer system,and the overlying quaternary consolidated sediments aquifer system.The aquifer system features and the groundwater formation and evolution were discussed,and the water resources and its exploitation potential were also assessed.