A new (discrete) model for random-pore aging in isochoric system with wall relief softening is proposed. The main criterion of the evolution of such system is the reduction of solid-gas interface area with time. The model allows simulations of the evolution of aging porous system with time, and estimations of free energy of the system. Equations of the model are used for simulations of the evolution of porous system with time. It is shown that the proposed model is effective for theoretical studies of processes of pore transformations by aging. (C) 2004 Elsevier Inc. All rights reserved.