Abstract: The coal mining industry in the Ordos Basin faces dual challenges of high costs for treating highly mineralized mine water and the difficulty of protecting groundwater resources. This study focuses on a coal mine in the border area of Inner Mongolia and Shaanxi, proposing a novel deep storage and reinjection technology combined with in-situ reduction, against the backdrop of complex hydrogeological conditions, increasing mine water inflow, and the high costs of membrane treatment processes. Firstly, based on the principle of "water quality priority," the study compares and analyzes the geological safety, water environmental safety, and characteristics of water storage and seepage media across different strata depths, identifying the Liujiagou Formation sandstone as the optimal reinjection layer. Secondly, the Liujiagou Formation sandstone is vertically divided into seven heterogeneous layers. Through indoor CT scanning and seepage experiments, the vertical heterogeneity, porosity, and permeability characteristics of the Liujiagou Formation sandstone are revealed, demonstrating that the third layer exhibits the best permeability, while the third and fifth layers have the highest static water storage capacity. This further confirms the Liujiagou Formation as a low-permeability, low-porosity sandstone aquifer. Subsequently, a three-dimensional hydrogeological numerical model of the thick Liujiagou Formation sandstone is established using GMS software. The model elucidates the evolution patterns of the single-well injection flow field, hydraulic influence radius, flow rate, and cumulative water storage under constant permeability conditions. Simulation results show that the maximum hydraulic influence radius reaches 466.1 m, and the cumulative water storage after 700 days of single-well injection reaches 1.805 4 million m³. Finally, two different deep storage and reinjection modes for groundwater resources are constructed, categorized into conventional and unconventional water resources. The proposed "micro-treatment + deep reinjection" mode, combining underground and surface reinjection, reduces costs by approximately 40% compared to traditional membrane treatment. The research findings align with China’s "zero discharge" policy for mine water in western coal mining regions, providing theoretical support for the resource utilization of mine water and ecological protection. The technology has been successfully applied in coal mines such as Hujierte and Nalinhe in the Ordos Basin, achieving coordinated exploitation of coal and water resources. This study holds significant implications for ecological protection and sustainable development in arid mining areas.