Porous aluminum sandwiches with the aluminum foam and dense steel sheets were fabricated by the friction stir processing (FSP) route. Using the fabricated sandwiches, failure tests were carried out under combined loading of tensile type and shear type. Under only shear type loading, two types of failure (i.e., tensile type failure and shear type failure) were observed. Under combined loading, tensile type failure firstly occurred, then shear type deformation markedly increased. The tensile strength and shear strength of porous aluminum could be approximately defined by the maximum principal stress and maximum shear stress, respectively.