Abstract: A new composite sealing material was prepared by taking coal-rock cuttings as base material, and supplemented by some other additives, such as binder, accelerating and expansive agent. The orthogonal design of four factors and three levels were used to design nine groups of different proportioning experiments, and the interaction mechanism among different components was studied with fluidity, compressive strength and expansion rate as indicators. Finally, the optimum ratio of composite sealing material, was obtained. And the combination effect of composite material and coal wall was also analyzed by SEM method. Then the field test was carried out at Xiadian Coal Mine, the results showed that the composite sealing material can significantly improve the gas drainage effect compared with the traditional cement mortar sealing method, the average gas concentration of drainage borehole increased from 22.2% to 36.5%, which reached the standard of gas utilization.