Abstract: In order to solve the existing problems of large construction volume, long construction time and poor structural closure, the paper adopts the technology of soft mould filling sand with high water expansion material, that is, increasing cement admixture and adding a certain proportion of early strong water reducer in filling materials, it can shorten the solidification time of filling material, improve the early strength of wall, improve the construction speed of fire dam, reduce the labor intensity of workers and improve the efficiency of filling in the lane. The application of this method is beneficial to the filling operation in the goaf area in advance.