Abstract: Due to the complex geological conditions and the lack of test materials, the influence factors of coal mine are random, fuzzy, grey and unknown, which can not determine the reasonable weight, which results in inaccurate evaluation results．To solve these problems, the D-S theory is introduced into the fuzzy comprehensive evaluation method. Using the method of conflict evidence synthesis in D-S theory, we eliminate the conflict between data fusion to determine the index weight, and solve the problem of too absolute traditional weight allocation process so as to provide a reasonable basis for the accurate evaluation of mine fire hazard rating． The improved fuzzy comprehensive evaluation method is used to evaluate the fire risk of Xingan Coal Mine．The case study shows that the D-S theory can take into account the uncertainty of the index in the fire risk assessment, and the fuzzy comprehensive evaluation based on D-S theory has high precision and high application value．