Abstract: The bending mechanical properties of aluminium alloy matrix gradient composites reinforced with SiC particles were studied using a bending test under three-point loading. The bending strength ratios R₁ and R₂ of the composites were put forward. The results show that the bending mechanical properties of the Metal Matrix Gradient Composites (MMGC) do not obey the Role of Mixture (ROM) law. The bending strength is remarkably influenced by the distribution way of SiC particles and bending direction.The MMGC can develop their full potential in bending properties when the matrix component is laid at the tensile side and the component with high SiC volume fraction at the compressive side. The potential of mechanical properties and the oriented features of the MMGC by the action of gradient stress are influenced by many factors such as the state, the macro-uniformity and the micro-continuity of materials. The bending strength ratios R₁ and R₂ can be used to justify the bending properties and the orientation of the composites.