Abstract: In order to study the deformation characteristics of concrete under different confining pressures and different curing cycles, the TAW-2000 test system was used to conduct triaxial mechanical property tests on concrete samples cured for 3d and 28d. The total energy, elastic energy and dissipated energy in the concrete deformation process were determined by the energy calculation method during the concrete loading process. According to the energy conservation principle, a constitutive model that can describe the stress-strain relationship of concrete was obtained. The comparison of model curves proves the rationality and superiority of the established constitutive model. The physical meaning of new model parameters is clarified. The results show that the previous models’ curves have a large deviation at the post-peak stage of the concrete stress-strain curve. However, the degree of fitting of the new model curve at the post-peak stage is higher. The model parameter γ can better reflect the brittleness and ductility characteristics of concrete. The model parameter n can better reflect the strength characteristics of concrete.