Aluminum alloy 2024 matrix composites reinforced with Al₂O₃particles, were prepared by rheo-compocasting, a process which consists of the incoporation distribution of reinforcement by stirring within a semi-solid alloy. The microstructures and characteristics of the interfaces have been studied using optical microscope and scanning electon microscope in 2024 aluminum alloy composites reinforced with Al₂O₃particles. The main results are as follows: (1) Al₂O₃particles were well distributed in composites by using rheo-compocasting. (2) As the addition of Al₂O₃particle increases, the average dendrite numbers and the hardness were increased. (3) Interaction between Al₂O₃particles and alloy 2024 resulted in the formation of Mg and Cu element rich region around the Al₂O₃particles.