We have evaluated the interfacial reactions of SiC fibre reinforced Al electrical power cable using low oxygen SiC fibre (Si : 62.4, C : 37.1, 0 : 0.5 mass%), and determined the relationship between the tensile strength and the amount of reaction products at the interface. The following are occurring at the SiC/Al interface: i) diffusion of Al atoms into the SiC fibre, ii) formation of needle-shape Al4C3 compounds, and iii) formation of Al9Si compounds. Formation of Al4C3 and Al9Si compounds at the interface causes the strength of SiC/Al composite electric power cable to deteriorate.