A 0.5 wt% GNP/Al composite was prepared by powder metallurgy and hot pressing. The numerical simulations and experimentsof porthole die extrusion were performed at 440 °C, 460 °C, 480 °C and 500 °C. The effect of extrusion temperatureon the microstructure and mechanical properties of the composites was studied. The results showed that the composite nearthe welding zone underwent dynamic recrystallization due to the large strain to form fine grains, some of which grew tocoarse grains because of the local high temperature. The extrusion temperature influenced the properties of the 0.5 wt%GNP/Al composite along both the extrusion and transverse directions. This influence is combined with synergistic effectson the recrystallization of the grain, fluidity and plasticity of the matrix, determined by the delamination, distribution andstructure of graphene and welding behavior in the welding zone. Therefore, the comprehensive mechanical properties ofthe composite reached the highest values in the extrusion direction and the transverse direction at 460 °C; the TEM imagesshowed that the graphene and aluminum matrix were in contact with each other via a small wavy transition overlapping zoneor that interaction forces caused by welding and shearing allowed the formation of a direct interface with the Al matrix. Thedeformed graphene formed a good interface with the matrix, ensuring outstanding mechanical properties in the welding zone.