In view of power quality problem caused by progressively increase of nonlinear devices of coal mine enterprise, evaluation index and comprehensive evaluation method of coal mine power quality were proposed. Firstly, evaluation index system of coal mine power quality was built according to influence of nonlinear equipment to coal mine power supply system; then, combination weight of evaluation index was decided by improved analytic hierarchy process (subjective weighting method) and entropy weight method (objective weighting method)finally, comprehensive evaluation of coal mine power quality was performed by combination of probability theory and fuzzy mathematics. Example analysis result verified rationality of evaluation index system and feasibility of the comprehensive evaluation method for coal mine power quality.