Abstract: After the application of Xiaolangdi reservoir,because of the change of water and sand conditions,the downriver type of Yellow River is in the movement strongly that causes the departure of irrigating gate and the rate of guarantee always keeps the low level.Once the method of milisecond blasting slotting is put into use,the main stream and the leading river will flow smoothly,which is an effective way to improve the guarantee rate of wandering reach.Its principle is to blow up a small notch then wash out with water so as to form the irrigating channel before the gate.The experiment shows that the quantity of detonator can influence the bound.In other word,the unilateral horizontal distance is ten times of the depth of explosion.The method can make the notch quickly and presses the sand and mud around the notch and it is easy to jump-start through the backfill of silver sand.