Abstract: In this paper, graphene-reinforced aluminum matrix composites were prepared by friction stir pocessing (FSP). The graphene distribution and defect were analyzed by OM, SEM+EDS and raman spectra, and the interface reaction between graphene and alumium was analyzed by XRD. The mechanical properties of the composites with difference graphene adding amount were studied. The results show that the interface reaction could be effectively reduced, and the graphen could be exfoliated further under the action of FSP force. Meanwhile, the graphene structure of graphene was destroyed gradually during the process of FSP. The graphene distribution in the aluminum matrix was closely related to the graphene adding amout, and more addition leads to the aggregation and stacking of the graphene layers, which affects the mechanical properties of the composites, especially the elongation. The simultaneous strengthening and toughening could be obtained by the appropriate graphene addition amount.