Hydrochemical analysis of groundwater reveals its composition and sources, providing a scientific basis for sustainable water resource utilization, ecological protection, and water-inrush disaster prevention. Moreover, water quality assessment not only determines groundwater suitability but also serves as a critical link connecting resource utilization, environmental conservation, and public health. To address these challenges, this study investigates 19 sandstone fissure water samples from the Qianyingzi Coal Mine. Hydrochemical characteristics were analyzed using ionic ratio analysis and statistical methods, whereas water quality assessment employed three distinct approaches: single-parameter assessment, F-value comprehensive evaluation, and fuzzy comprehensive evaluation. The resulting findings provide essential scientific support for strategies related to safe water usage, pollution control, and sustainable resource management in coal mining regions. The results indicate that anions in the fissure water are dominated by SO₄^2- and HCO₃^-, whereas cations primarily consist of Na⁺ and K⁺. The hydrochemical type is classified as SO₄·HCO₃-Na+K, reflecting the dominance of sulfate and bicarbonate anions combined with sodium and potassium cations. Furthermore, ionic ratio analysis revealed that the hydrochemical composition primarily stems from the dissolution and weathering of rock salt, as well as processes involving carbonate and sulfate minerals. Based on the F-value and fuzzy comprehensive evaluations, the fissure water was predominantly categorized as Class IV and V (according to national standards), signifying poor quality with potential environmental and health risks. These outcomes establish vital theoretical foundations and offer practical guidance for mitigating mine water hazards, optimizing groundwater exploitation, and enhancing ecological protection strategies in mining areas.