Abstract: A three-dimensional (3-D) finite element model of the actual structure of closed-cell aluminum foam was reconstructed based on X-ray computed tomography. The mechanical response and deformation mechanism of aluminum foam under quasi-static uniaxial compression were investigated through numerical simulations and experiments, especially the deformation mode of the foam in plateau stage and densification stage. The results show that at the beginning of plateau stage, the deformation band occurs and the dominant deformation mode of cell edges and cell walls is plastic bending. During plateau stage, the deformation mode switches to plastic wrinkling and buckling. As densification stage starts, the cells within deformation band are seriously collapsed, and are ‘biconcave disks’. The numerical simulations are consistent with experimental measurements. Thus, the model is validated, providing a basis for further investigation on the influence of corresponding physical factors (e.g. relative density and loading speed, et al) and deformation mechanism on the energy absorption capability of closed-cell aluminum foam.