Abstract: Changes in pore morphology and wrinkles on the inner surface wrinkling of pores of Al foams prepared by powder metallurgy (PM) were investigated for different foaming time. The results showed that the bubble shape evolves from near spherical pores to polygonal ones with foaming time. With Plateau borders become smaller gradually, cell walls get thinner, even local fracture and, finally, the inevitable rupture and coalescence of pores. The crack-like pores found in the early foaming process is just the inherent characteristics of Al foams prepared by PM, which are caused by the release stressing in the direction perpendicular to compacting load inside the PM precursors. The pore evolution process is reflected by the wrinkles on its inner surface, i.e. the inner surface is rather smooth with a few wrinkles in the early foaming process, then the wrinkles are bulging out and, at last, the wrinkle belts form on the inner surface due to gravitational effect and increasing surface energy.