Interphase boundary sliding and fracture, and the effect of different types of growth faults on the processes have been studied microscopically on the lamellar Al-CuAl//2 composite. It has been shown that sliding can occur at every two interphase boundaries, probably originating from a special structural feature of interphase boundaries in the eutectic alloy composite. It has also been demonstrated that extensive interphase boundary sliding can occur being associated with the presence of growth faults such as lamellar termination and ripple or misfit boundary. We may consider that the localized sliding very likely introduces the bending stress which facilitates the fracture of brittle CuAl//2 ( THETA ) layer controlling the ductility and fracture of the composite. It is concluded that the presence of growth faults is an important key factor controlling interphase boundary sliding and fracture of the lamellar Al-CuAl//2 eutectic composite at high temperatures.