Abstract: Taking the loose medium above goaf as the research object, the mechanism of self-repairing of blockage of loose medium was studied and the technology was successfully applied. The clogging and self-repairing technology for the loose aquifuge was mainly affected by flow, sediment load and suspended sediment size. If the flow is too large, the loose aquifuge is washed off. When the flow rate is slow and the sediment load is large, it is easy to clog and self-repair for the loose aquifuge above goaf. When the particle size is less than 0.075 mm, it is conducive to the clogging and self-repairing technology. The type is surface-internal clogging and surface clogging effect is more obvious. The effect of the clogging and self-repairing technology is proportional to clogging time. The longer the clogging time is, the smaller the permeability is, and the more obvious the effect is.