Hydraulic rock drill is a kind of impact machine which the piston is driven to impact drill rod on the high-pressure oil. The impact system is the key components of the hydraulic rock drill, its performance directly influences the performance of hydraulic rock drill. In this paper, analysis and experimental study on dynamic characteristics of impact system of valve type hydraulic drilling machine were researched based on the wave mechanics theory, testing technology and numerical simulation. Stress wave curves of the drill rod under different impact velocity were obtained. Numerical simulation and experiment were carried out. The simulation results are shown to be fundamentally consistent with the experimental results. The development process of hydraulic rock drill can speed up through the numerical simulation. This work provides the basis for structure optimization design and energy efficiency assessment.