In this paper, a successful attempt is demonstrated to prepare graphene/aluminum composites by in situ exfoliation of graphite flakes(GFs) using rotational friction extrusion(RFE) method. It is found the GFs were broken on a large scale and uniformly dispersed into the aluminum matrix during PRE. EBSD analysis indicated the grain was significantly refined, high angle grain boundaries were increased. As revealed by HRTEM that a number of 5-12 layer graphene can be peeled off from the GFs owing to the severe plastic deformation of RFE, and there exited obvious transition at the graphene-aluminum interface due to the diffusion of carbon atom at the broken graphene edge, which provided an an efficient load transfer for the composites. The yield strength and tensile strength of the prepared composites are 76.4MPa and 163.2MPa with 0.82 wt% addition of GFs , which are 91% and 71.4% higher than the RFEed base metal (1060 Al), respectively. Meanwhile, the elongation of the composites is 25.3%, and a good strength-ductility balance is obtained. This work may opens new opportunities for the fabrication of high-performance graphene/metal composite toward industrial application.