Abstract: The existing slotting( reaming) device has low cutting efficiency for medium hard or hard coal seam,and there are relatively few supporting safety protect ion measures,which can not realize the remote operation of slotting. In order to solve the problem of safe and efficient seam penetration enhancement in medium hard 0 r hard coal seam,it is necessary to develop a complete set of slotting device with higher pressure.On the basis of comprehensive consideration of equipment efficiency, slotting depth and required flow rate of slotting slag,a high-pressure clean water pump was developed; by analyzing the distribution law of borehole flow field,and accor ding to the theory of water jet,a high-low pressure conversion slot cutter was developed; Based on the drilling slag discharge principle,the overall processing technology was adopted to develop the shallow spiral integral drill pipe; based on the narrow slot viscous fluid flow theory,the ultra-high pressure rotating water tail was developed using the gap seal design; based on the variability of underground coal mine roadway conditions,and according to the rated pressure and rated flow of high-pressure c| ear water pump,the design requirements of the overflow valve were determined,and the high-pressure remote control was developed; the pressure resistance and resist ance loss along the long-distance slotting operation were comprehensively analyzed,and the ultra-high pressure hydraulic hose was developed. Through the developme nt of key components,the ZGF-10( A) ultra-high pressure hydraulic slotting device has been successfully developed. The complete set of equipment has a working pre ssure of 100 MPa and it has the integrated function of dilling and cutting,which can realize remote control of more than 100 m.The safety protection device has formed a safety protection system for ultra-high pressure hydraulic transmission. At the same time, safety tests have been carried out on 8 items including no-load operation,wo rking pressure,working flow,sealing performance and pressure resistance of the complete set of equipment,and the contents of the tests were in line with the state relat ed testing requirements. The field application results show that: the ultra-high pressure hydraulic slotting device is used to relieve pressure and increase permeability of coal seam. The average single cutting coal output of through seam drilling is 0.85 t,and the cutting radius is 1.78 ~ 2.18 m,which can increase the pure amount of gas drainage by more than 2.0 times and shorten the time of reaching the standard by more than50%; under the condition of 47% reduction in the drilling volume of the bed ding drilling,the pure amount of single hole gas drainage can be increased by2.0 ~ 2.5 times ,and the cycle construction period of driving can be shortened by more tha n 60%.It shows that this method has high fficiency in seam cutting,and has significant anti-reflection effect in seam pressure relief after seam cutting