The electric hammer is a kind of machine with producing and transferring energy by impact. Firstly, ternary impact system dynamic model of electric hammer was established based on structure characteristics and wave mechanics. Secondly, numerical simulation method was proposed for electric hammer impact system by means of transmission and reflection relations theory. Finally, numerical simulation and experiment were carried out for a certain type electric hammer. The results showed that the simulation result is consistent with the experimental result. The conclusions are instructive to dynamics analysis and optimal design of electric hammer impact system.