<p>Graphene-like coatings (C atoms) were introduced to MgO-dispersion-strengthened Al alloys to contribute to the high-density uniform distribution of MgO in Al matrix, but the effects of the added C on the MgO/Al interface remain unclear so far. Here, we resort first-principles calculations to resolve this issue. The values of surface energies for stoichiometric surfaces (001) and (010) of MgO were accurately obtained. The non-stoichiometric surface (111) is closely related to temperature and pressure, of which the surface energy of Mg-termination exhibits opposite trend as compared to O-Termination. The lowest energy structure of MgO (001) /Al (001) structure with segregated C atoms was clarified at the atomic degree. Solute C atoms preferentially occupy the vacant sites between Al atoms on the first layer of the Al matrix side, improving the interface strength significantly.</p>