Abstract: A phenomenological model of shock initiation and detonation of heterogeneous explosives is implemented in the one-dimensional hydrodynamic code based on the method of characteristics. Since there is no artificial viscous term to smear the shock, we can get a clear picture of the simulated structure of detonation wave. We have calculated Unsteady detonation process of PBX-9404 and the results are quite well consistent with the experiment data.