The deep oil and gas formation has strong abrasiveness, high hardness and poor drillability, which are the main causes of low ROP. Percussive drilling technique can greatly improve the ROP of hard formation. In order to improve the impact force of the drilling tool, a new type of drilling tool with impellers as pulse source and Helmholtz pressurized cavity was designed. Through the ground test, the pulse impact performance of the tool was compared, and the effects of different working parameters(flow rate) and the structural parameters of Helmholtz pressurized cavity(cavity diameter、cavity length and inner wall collision angle) on the output frequency、pressure amplitude and pressure loss of the tool were studied. Finally, the parameters of the enhanced pulse jet generating mechanism were optimized. The results show that the enhanced pulse impact speed-up tool can increase pulse amplitude and adjust the pulse frequency from 4Hz to 12.5Hz, which is suitable for drilling in hard formations. With the increase of cavity length and diameter, the impact frequency decreases continuously. When the inlet diameter of Helmholtz pressurized cavity is 40mm, the cavity diameter is 80mm, the cavity length is 70mm and the inner wall collision angle is 60°, the pulse jet output characteristics reach the best with the increase of displacement. It provides a new idea for the development of percussion drilling tools.