Abstract: In coal mine safety evaluation, the determination of index weight is particularly critical, which plays a decisive role in the evaluation results. At present, there are some shortcomings in the evaluation of internal fire in coal mine, such as few index selections, difficulty in determining index weight, unclear definition of evaluation grade and so on, which affects the accuracy of the evaluation results. On the basis of these, the evaluation system of coal mine internal fire is constructed based on four factors: coal seam geological occurrence, development and mining technology, coal seam spontaneous combustion tendency, ventilation condition and goaf management, and coal seam thickness, coal seam inclination and other 24 factors as the third-level index. By using the decision model and the Euclidean distance function, the subjective weight of the analytic hierarchy process and the objective weight of the entropy method are effectively integrated to obtain a more reasonable combined weight. The combined weighting-matter-element extension model is used to evaluate the internal fire in a coal mine. The result is “safer” grade, which is consistent with the engineering practice. The model is compared with the traditional evaluation method, the model is not only accurate, but also can reflect the degree of deviation within the evaluation grade, and can effectively improve the accuracy of the evaluation results.