There are obvious differences in the water chemistry and water quality characteristics of large quantities of mine drainage produced by the mining of the lower and upper coal groups in the shallow coal seam in the Inner Mongolia-Shaanxi connection area. In order to accurately grasp the change characteristics of mine water quality before and after coal mining in the lower group, 12 groups of coal water samples in the upper group and 12 groups of coal water samples in the lower group were collected, a total of 24 groups of water samples were collected, and the water quality was completely analyzed. The general water chemical characteristics, the concentration of ion components and the change characteristics and control factors of the main ion proportion were analyzed, and the water quality was evaluated by AHP-comprehensive pollution index method. According to the evaluation results, the utilization of mine water resources is discussed. The results show that the TDS value of mine drainage from the lower coal group increases, and the type of water chemistry changes from HCO₃·Cl-Na type to HCO₃·SO₄-Na·Ca type from HCO₃·SO₄-Na Ca. The cations in mine drainage are mainly K⁺+Na⁺, and the anions change from HCO₃⁻ and Cl⁻ to SO₄²⁻ and Cl⁻ type. The hydrodynamic conditions and the intensity of leaching were the main factors that caused the change. The water quality evaluation results show that the water quality of the coal mine well of the upper group is better than that of the coal mine well of the lower group. The mine water of the study area is not suitable to be used as drinking water and irrigation water. It is suggested to divide the water quality by the mining area, and the cleaner mine water of class Ⅱ~Ⅲ should be used as the domestic clean water or industrial production water.