Abstract: To realize the in-situ utilization of solid waste from power plant, a kind of porous plugging material with fly ash was developed to apply it in working face end-plugging. The foaming and mechanical properties of the porous end sealing materials of fly ash with different particle sizes were tested in the laboratory. The test results show that with the increase of fly ash particle size, the porous end sealing materials show the characteristics of constant solid density, decreased foaming density, increased porosity, decreased strength and material tightness. Therefore, in the field application process, appropriate mechanical grinding to reduce particle size, grading and screening of fly ash with small particle size can be used to improve the comprehensive performance of fly ash-based multi-pore materials. Numerical simulation and underground application results show that the sealing material has good compressive strength and sealing effect, and it can effectively solve the problems of air leakage in the goaf and CO produced by oxidation of residual coal at the end of the goaf when it applied to the end of the goaf.