Abstract: Because of the runaway of wellhead caused by the long time conflagration,it is very difficult to extinguish the fire and to kill the well in Ba33 gas well.Based on the practice to deal with this accident,this paper introduces a effective measure to put out the conflagration by the combination of water and powder.and advances a design method of the optimum parameters of hydraulic sand jetting cut and the soft metal gasket in the light of the simulation test and field application.