In this paper,throush the analysis for microscopic void model the more realisticand simplified description of growth and nucleation of voids and softening function has been derivedfor isotropic and kinematical hardening materials.The damage evolution equation is embed into anew incremental endochronic elaStoplastic constitutive equation for large deformation,and a damageconstitutive equation has been got.The effect of void evolution on the constitutive equation is denoted by a softenins function w(f) and an it6m reflecting mat6rials plastic expand.A numerical algorithm and finite element program for large elastoplastic deformation of damage materinls are finished.Finally they has been applied to the analysis of the necking of tensile cylinder specimen.Thecomparison between the calculated results and the experimental data show satisfactory agreement.