In order to characterize the dynamic mechanical behavior of polymer bonded explosives (PBX), a macroscopic elastic-viscoplastic constitutive relation has been developed, coupled by the micromechanical damage mechanism based on the macro crack statistical method. Dynamic compressive and fracture test of the PBX(64%RDX and 20%Al and 16%HTPB) have been carried out, and the material contants and algorithm for the model have been presented. By comparing with the dynamic compressive test data and simulation results of PBX, this model can predict the mechanical deformation process under different loading conditions, so that it can be spread for the deformation analysis of heterogeneous explosives.