A computer system for displacement sensor is developed to obtain the real-time curve of the liquid porosity of molten Al alloy foam. The relationship between the curve of P1-t and the change of the shape of the cells (spherical, similar spherical and polygonal) in the foaming process is analyzed. The changes of cell diameter and cell wall thickness are studied. And the the controlling methods of a new Al alloy foam with spherical pores, Iow porosity and high strength are developed on this basis. Also, the stress-strain curve during compressive deformation and energy absorption characteristics are investigated and compared with polygonal pore Al alloy foam with high porosity.