High entropy alloy is a novelty structural and functional materials. For the excellent interfacial wettability between HEAs and Al alloy, the interfaces of HEAs-Al is well-bonded. In this paper, the Al_0.25Cu_0.75FeNiCo particles were used as the reinforcement to improve the strength and ductility of aluminum alloy. The effects of HEAs content on microstructure and mechanical properties of the composites were investigated. Microstructure observation showed that the HEAs particles were distributed uniformly in the composites. With the reinforcement content increasing, particles clustering were found in local region. Results showed that the modulus and hardness of the composites increase with increasing of reinforcement content. While the tensile strength and elongation of the composites increase firstly then drop with increasing of reinforcement content. At a reinforcement content of 5%, the maximum tensile strength and elongation of the composites is 437.6 MPa and 11.42%, which were 20.54% and 36.6% higher than those of the aluminum alloy matrix. The excellent comprehensive mechanical properties is due to the well-bonded interfaces of HEAs-Al.