According to the fire fighting experience and selected Maodi Mine actual situation of coal seam geology structure, drench water of coal face, around working face mining situation, the depth of coal seam, surrounding rock temperature, mining rate of working face 16 evaluation factors, the spontaneous combustion risk assessment model was established, by the membership function of each evaluation factor to determine its single index measure, by unknown measure theory calculated the model, the results showed that working face in larger and smaller drench water cases of spontaneous combustion risk degree were "high" level, in the process of coal mining had a larger water spray, can reduce face the danger of fire.