Abstract: In improving the efficiency of gas extraction from soft and low permeability coal seams, the traditional hydraulic punching method requires drilling, lifting the auger, lowering the hole-making device, lifting the auger and then lowering the screen pipe for gas extraction. In order to solve the problems of its complicated process and high-risk factor, the technical parameters of hydraulic punching suitable for broken soft coal seam are determined by combining simulation results with field experiments based on Fluent and Ls-dyna simulation. The results show that the cavitation nozzle with nozzle diameter of 2.8 mm has better coal breaking ability than the common nozzle; the best effect of breaking coal is achieved when the punching time is maintained at 30 min/m, the pump pressure is kept in the range of 12 MPa to 20 MPa and the rotational speed is maintained in the range of 90 r/min to 110 r/min during the hole making period. A total of 136 drill holes were constructed, and the average coal punching volume of 1.07 t/m was calculated, and the coal seam permeability was greatly improved.