In recent years, graphene has attracted a lot of attention as a reinforcement to enhance aluminum (Al) matrix composites due to its two dimensional structure and excellent mechanical properties. However, there are still some obstacles that limit the performance of the composites, such as uniform distribution of graphene oxide (GO) and the interfacial bonding between GO and Al matrix. In this work, Cu2+ ions acting as a bonding bridge were added into GO/Al powder suspension to improve the distribution of GO sheets on Al powder via a simple electrostatic adsorption method. Then, vacuum hot-pressing sintering was applied to fabricate bulk composites, and their mechanical properties were investigated. The results showed that doping 3?wt% Cu2+ ions illustrated the best dispersion of GO on the surface of Al powder, meanwhile GO was maximally reduced. Compared with unreinforced Al, the hardness, compressive strength and flexural strength of the 3?wt% Cu-doped bulk composite were increased by 121%, 120% and 28%, respectively. However, the mechanical properties were deteriorated after doping 5?wt% Cu2+ ions, due to the aggregation of GO on the surface of Al powder. This was attributed that Cu2+ ions had a critical coagulation concentration in aqueous GO suspensions. It was expected this work could offer some useful information for preparing graphene reinforced metal composites.