Abstract: By simplifying one-dimensional two-phase flow continuum mixture model and introducing the particle number conservation assumption, the computational model of steady compaction waves in granular explosive was established. This model could be used to predict final pressure, final volume fraction, solid density, and radius and particle number density in porous HMX material. Tait EOS and Hayes EOS were used to analyze steady compaction waves in porous energetic materials and it was revealed that the analysis of using Hayes EOS was more proper than that of using Tait EOS. It was found that there was a shock process for compaction wave travelling with supersonic speed, but no shock process existed for subsonic compaction wave. At last, the compaction wave speed, the final pressure, final volume fraction and compaction zone length were studied as the function of initial volume fraction and piston velocity.