Abstract: The protection of water resources in mining has aroused much concern in Eastern Ningxia coal production base which is characterized by the fragile ecological environment and scarce water resources relatively. The authors calculated the maximum height of water flowing fractured zone in the first coal seam mining using the formula method and the three measured data. The difference value between the computations comprising the first coal seam, the main aquifer and the height of water flowing fractured zone could be used to predict influence of coal mining on the groundwater. According to the results obtained, the height of water flowing fractured zone is generally 20~80m, and the northwest Lingwu mining area of more than 180m possesses an area of about 5.9km²; in the Carboniferous-Permian coal mine area, the water flowing fractured zone has penetrated the Shihezi Formation and reached the main aquifer (Cenozoic aquifer) with 7 drill holes, such as 2808 and 2809; in the Jurassic coal mine area, the water flowing fractured zone has communicated the surface with 9 drill holes, such as 2702 and Yan1. The influence degree of the first coal seam mining for the aquifer has been divided into four types, i.e., large, larger, affected and weak, with the proportion being14.7%, 40.31%, 18.65% and 26.34%, respectively.