Abstract: Aiming at the problem of insufficient water richness in the aquifers of Jurassic sandstone layers in Shaozhai Coal Mine of Lingtai mining area, Gansu Province, the pore characteristics of sandstone with different particle sizes and their impact on aquifer water richness are explored at the micro-level by adopting technologies of cast body thin section microscopic observation, high-pressure pressing pump experiment, and ordinary thin section analysis. The research finds that the coarse sandstone has the highest porosity and permeability, and has excellent water storage and fluid migration performances; The middle sandstone comes second; However, the fine sandstone shows insufficient water storage capacity due to its lowest porosity and permeability. The research reveals the correlation between pore type, morphology, and distribution with porosity and permeability. Based on the above theoretical analysis, the improvement strategies for optimizing the water storage performance of aquifers are proposed, providing scientific basis for water resource development and water disaster prevention and control in mining areas. The research results significantly improve the understanding of the formation mechanism of aquifer water richness, and have important reference value for coal mine production safety and resource protection.