Abstract: The interfacial bonding and the elastic deformation of SiC_P/1100Al and SiCP/7075Al composites were compared. The results indicate that the elastic moduli of the two kinds of composites are highly different due to the difference of those interfacial bonding, load transfer that occurs through interface between the matrix and the reinforcement is the important strengthening mechanism during the elastic deformation of the composites, and the strengthening effect of the mechanism depends on the interfacial bonding between the matrix and the reinforcement.