Abstract: Aiming at the characteristic that confining pressure has a significant influence on the mechanical properties of Polymer bonded explosive (PBX), a quasi-static constitutive model considering the effect of hydrostatic pressure called the Boltzmann-P model was proposed on the basis of the existing Boltzmann model. A nonlinear calculation method for the constitutive model and a numerical method of transforming the one-dimensional constitutive model into the three-dimensional model by using Mises equivalent stress strain and introducing Poisson's ratio are developed. Through secondary development, the constitutive model and the practical application of the corresponding algorithm were realized. Through the calculation of unit elements, it is shown that the description accuracy of the Boltzmann-P model is better than that of the Boltzmann model without and with confining pressure. The rationality and accuracy of the Boltzmann-P constitutive model, the corresponding algorithm and the developed subroutine are verified.