Abstract: In this paper,the actuality of water disaster and its control are analyzed.It is introduced that the dim judgement method of forecasting water yield,which is finished on the basis of water content division of roof aquifer by using the method of drawing up with the information.To take 4318 working face in Xinlongzhang coal mine as a example,the water yield from top water-bearing body is forecasted;the water yield is divided 3 grages.Normal water yield is 0.5~1.5 m³/min,maximum water yield is 2.25 m³/min,that coincides with measured water yield.