Abstract: Based on Huang (Peking University) and Wang (Peking University)'s theory as well as the second thermodynamic law, the nonlinear compressive behaviors of closed-cell aluminum-alloy foams were studied at finite deformation. By means of introducing the internal variable and evolution equations of internal variable, the expressions of effective power-law potentials and stresses were presented whick taks meso-structural parameter and viscosity effect into consideration. With the presented theoretical models, some numerical examples were conducted to analyze the influences of micromechanics approaches, porosity and viscosity effect on the stress-strain curves of aluminum foams. The results show that the model predictions are basically agree with the experimental result. In addition, it is found that the model predictions considering the viscosity effect tend to the model predictions without considering the viscosity effect when the viscous coefficient becomes larger.