In order to reasonably allocate the mine water in the regional water supply system, Uxin Banner, a large-scale coal mining area, is taken as the study area to predict the future water supply and water demand. Meanwhile, the water supply rules and an allocation model are established with the consideration of multiple water resources including mine water, so as to sort out the optimized allocation scheme of multiple water resources. Results show that compared with 2020, the water supply structure of Uxin Banner will change significantly in 2025 as a result of the expansion of coal mining scale. The groundwater supply will reduce by 44.9% while the mine water supply will increase by 1.4 times. The massive supply of mine water will replace the groundwater supply, which can solve the problem of local groundwater overexploitation. Limited by the total water consumption control index, the water shortage of the whole banner will reach 19.13×106 m3 in 2025. In the future, it is necessary to reduce the area of farmland to control the growth of water demand. There is an urgent need for large-scale utilization of mine water in Uxin Banner, but there are practical problems such as high water supply cost and inconsistent water intake permit. The large water network project (under construction) in Uxin Banner provides engineering conditions for establishing the complementary relationship of local surface water, Yellow River water, mine water and recycled water, which is conducive to eliminating the instability of mine water and ensuring the stable supply of water resources.