Based on problems of the poor effect of yellow mud Irrigation plugging, hard recycling of cement plaster, poor strength and short useful life of gel plugging material in coal seam spontaneous combustion fire prevention, combined with high strength, high temperature resistance, long useful life of coal ash gel, its working principle and technical characteristics were analyzed, the technology process and operation steps were give. The result showed that the technology with good consolidation performance of water, cooling and plugging performance, avoided disadvantages of poor strength, high temperature resistance and short useful life of previous gel injection fire prevention, the technology could solve the water leakage problem in gel injection and avoid spontaneous fire in mine effectively.