Abstract: In order to solve the problems such as the influence scope of extraction is small and the extraction effect is poor on bedding drilling in low-permeability hard coal seam, the high pressure water jet failure process of the hard coal seam was analyzed, and the numerical simulation method was used to study the mechanism of pressure relived and permeability enhanced of ultra-high pressure hydraulic slotting, a new set of ultra-high pressure hydraulic slotting device was developed.In addition, the application effect of borehole drilling and ultra-high pressure hydraulic slotting along the strip of coal roadway in hard coal seam was investigated on site.The results show that after the use of ultra-high pressure hydraulic slotting, the permeability of hard coal seam is increased by about 20 times, the average gas extraction volume of borehole is increased by 2.0 to 2.5 times, the time required to reach the standard is reduced by more than 67%, and the monthly driving speed is increased by about 50%.During tunneling, there is no abnormal gas phenomenon, and the tunneling in hard seam coal roadway strip is safe and fast.