Explosion seismic waves are numerically studied with a non-stationary random process model. Based on energy conservation and experiential relation, an envelope function of acceleration amplitude and power density of explosion seismic waves is proposed, in which the effects of distance and mass of explosive are considered. The model parameters are determined by using the measured data. A practical simulation method of single-point, two-point (little-difference) and multi-point (little-difference) explosion seismic waves is also presented. Numerical simulation results show that the simulated history of explosion seismic waves can well reproduce some characteristics of explosion seismic waves.