Abstract: In order to solve the problem of controlling rock burst in 21105 working face of Hulusu Coal Mine, the ultra-high pressure hydraulic jet slotting stress-relaxed and rock burst prevention technology of free wide coal pillar was put forward. Firstly, the slotting depth of coal seam by high-pressure hydraulic jet and the stress transfer law after coal pillar slotting were studied by theoretical analysis, and the ultra-high pressure hydraulic jet slotting stress-relaxed and rock burst prevention mechanism based on unloading and load reduction and increasing plastic barrier zone was proposed. Then, FLAC^3D numerical simulation method was used to study the stress distribution law of coal and rock under different slotting conditions of free wide coal pillar, and the slotting process parameters of coal pillar were obtained. The industrial application has been carried out in 21105 working face of Hulusu Coal Mine. The microseismic events, stress levels and cuttings in the test area were significantly reduced compared with the adjacent areas. The results show that the ultra-high pressure hydraulic jet slotting technology can effectively change the stress distribution of coal and rock mass, transfer the high stress area to the deep coal and rock mass, increase the range of plastic barrier area near the mining space, and effectively prevent coal mine rock burst accidents.