Abstract: Meihe Mine is a resource exhausted mine where coal-seam is steeply-inclined and extremely-thick. Once encounter water,roof and floor of the coal-seam are easy to form mud-sand flow and result in disaster. On the basis of researching mud collapse mechanism,this paper put forward combined prevention technology of mud-sand flow including "exploring,discharging,dewatering,draining",which was applied in 0305 residual-mining face of Meihe 3rd Mine. Safe mining-to-caving ratio was determined 12m and residual mining was successful. Coal resources recovery ratio was added and mine service time was prolonged.