Abstract: The cell-size effect on compressive properties of aluminum alloy foam is analysed. A variety of experiments on AA6101 Aluminum Alloy foam, which includes 4 densities and 3 cell-sizes, are carried out under dynamic loading on SHPB and quasi-static loading on MTS 801, respectively. Cell-size has a significant effect not only on the crushing stress and plastic modulus of aluminum foam, but also on the strain-rate sensitivity of material of this kind. Energy absorption efficiency is also investigated in the paper.