The magnesium alloys have poor corrosion resistance because of their low equilibrium potential and loose oxide film, while the aluminum and its alloys have good corrosion resistance due to their compact oxide film. In this study, a kind of aluminum and magnesium bimetallic bars, 6063 aluminum alloy-clad AZ31B magnesium alloy bars, were acquired through hot extrusion. The experimental results showed that the extrusion temperature of 653K or lower, as well as an extrusion speed of 2m/min or lower be used during the extrusion. The interfacial structure and mechanical properties of the bimetallic bars were studied. The interface between aluminum alloy and magnesium alloy was metallurgic bonding with the shear bonding strength of 53Mpa for as extruded sample. As annealing temperature or holding time increased, the jointed layer between aluminum alloy and magnesium alloy was broadened, which decreased of shear bonding strength, indicating that the heat treatment is deleterious. The bimetallic bars have lower identity, good corrosion resistance and preferable mechanical properties, which are promising constructional materials.