Rock is regarded as particles with internal friction. The process of rock failure under impact loading is analyzed with mechanical model; and the dynamic behavior is described. The deformation near impact loading in rock is similar to one-dimensional deformation. The stress wave form the loading can be regarded as short-wave whose characteristics have sharp varieties in a cabined zone near wave front. The stress state will transfer from elastic state to internal friction state; finally liquid hydrodynamics state

with strong or leak movement of particles.