Abstract: The reasonability and reliability of a rigid-plastic meso-damage constitutive theory were examined for porous composites reinforced by rigid particles. The numerical calculations based on the constitutive theory were compared with the tensile experiments on Al matrix composites reinforced by SiC particles. The results show that the constitutive theory agrees with the experimental stress-strain curves, so this constitutive theory can be put into numerical simulation and predict the mechanics properties of the composites reinforced by rigid particles. Based on the above, the ductility and evolution law for void and particles were discussed in this paper.