Abstract: SiC_p/6063Al composites containing high and low volume fraction SiC after electroless nickel plating were soldered by using Sn-3.0Ag-0.5Cu-3.0Bi solder in vacuum. The microstructure and components of the interface were studied by means of SEM and XRD. The results show that in the soldering process, the solder reacts with the nickel layer and continuous scalloped intermetallic compound forms at the interface and the IMC is (Cu, Ni)₆Sn₅. The IMC layer is arranged compact and its growth direction perpendicular to the interface point to solder. In the soldering process, the growth of IMC can be divided into a faster growth rate stage and a slower growth rate stage. At the soldering temperature of 270℃, when soldering time is extended from 10 min to 40 min, scallop-shaped morphology of IMC keeps unchanged, the grain of IMC becomes larger. Thickness of IMC layer increases, but its growth rate is gradually reduced with increasing soldering time. The shear strength of the soldered joint improves continuously.