In this paper, the simulation of the commpress properties of Al foam was investigated by finite element methods. The simulation results show that the compressive yield strength of Al foam is consistent with the theoretical model of Gibson and Ashby. The yield strength of Al foam decrease with the increase of porosity, and the yield strength decreases significantly with the increase of porosity. The density of Al foam is proportional to the compressive strength. At a certain porosity, the ratio of sample size and the aperture have an extremely important effects on compressive behavior of aluminum foam. When 4 ≤ D / d <8, with the increase of the ratio of D / d, the plastic deformation plateau and the compressive strength of metal foam is increasing ; on the contrary ,when the ratio> 8, with the increase of the ratio, the plastic deformation plateau is decreasing, the compressive strength keeps constant.