Abstract: The effect of discontinuous interfacial phase Al₄C₃ on the interface bonding of SiC/Al composites was discussed by using the first-principle approach based on density functional theory and experimental method, in comparison, the interface without new phase was also investigated. The results show that the C atom adsorbed on the surface of Al(111) is the most stable at the bridge position, and the adsorption energy of C atoms decreases gradually with the increase of C coverage. The formation of a discontinuous Al₄C₃ product leads to the interface changing from SiC/Al to (SiC+Al₄C₃)/Al, and their corresponding work of interfacial adhesion increases from 0.851 J/m² to 1.231 J/m², which is attributed to the fact that covalent bonds or ionic bonds are formed between C atoms with Al atoms when C atoms are adsorbed on the surface of Al, and covalent bonds between C atoms with Si atoms. In addition, the calculated adhesions of SiC/Al, (SiC+Al₄C₃)/Al system by first-principles are in good agreement with these of experiment, which has high reference value.