In this paper the result of theoretical assessment of the interface layer thickness impact on residual stresses in composite material based on aluminum alloy, reinforced with aluminum oxide fiber was presented. The model of two-layer cylindrical inclusion of a plane axisymmetric problem of thermoelasticity was used for the calculation. Liability of theoretical or experimental determination of the optimal (maximum) thickness of interfacial layers in the composite was shown, this is related to increased level of residual stresses in the material, while increased the interfacial layer thickness. At the same time insufficient thickness of interfacial layers, included magnesium spinel and copper, leads to a reduction of oxide fibers and aluminum matrix contact resistance, and consequently, it reduces all operational characteristics of the material.