Abstract: During coal mining, mine water containing large amounts of pollutants such as suspended solids and heavy metal ions is produced. If discharged directly without treatment, it will cause serious pollution to the surrounding water environment. This study investigates a water quality evaluation method for coal mine water based on the fuzzy entropy weight method. A set of evaluation factors and a set of evaluation grades for coal mine water quality are established. The weights of the evaluation factors are determined using the entropy weight method. A fuzzy membership matrix is constructed based on the membership functions of each evaluation factor corresponding to the water quality grades. By multiplying the factor weights with the fuzzy membership matrix, a fuzzy comprehensive evaluation model is obtained to realize the evaluation of coal mine water quality. The results of a case study show that the proposed method can objectively and accurately evaluate the water quality of coal mine water.