Abstract: Using surface alloying technique, copper layer and nickel layer were deposited on the SiCp/6063Al composites with 60% volume fraction of SiC. Then, SiCp/6063Al composites before and after surface alloying were vacuum brazed respectively. The effects of copper layer and nickel layer on the shear strength of the brazed joints were studied. The results indicate that the two plating layers combined with base metal compactly. As prolonging the heat preservation time, the shear strength of the brazed joints rose synchronously at 570℃. The brazed joint of the composite with copper plating on surface had higher shear strength than that with nickel plating, and the top value hit 55.4 MPa. The shear fracture occurred on the inside of composites and in the brazing filler metal. Nickel plating decreased the shear strength of the joint.