Abstract: The punch loading process was simulated by three-dimensional discrete element software PFC3D based on discrete element method (DEM), the effects of punch loading speeds on the transmission wave of metal powders generated by the impact and the pressure distribution on the sidewall were investigated. In the results, for the discrete media, the stress wave propagation under impact loading is determined not only by the wave impedance of particle material, but also by the particle motion and force chain formation. By comparing the force on the bottom of female mold in the different loading speeds, it is found that the peak of transmission wave increases linearly with the increase of loading speed. The lateral pressure peak on different positions is obtained by means of the side wall of female mold. It is found that the pressure on the sidewalls is present as the valley-like distribution, and the propagation and distribution of the inter-particle force chains are analyzed.