Аннотация:The epitaxial relations were examined for some crystallographic orientations of the Ga-nitride and substrates like Al2O3, ZnO MgO, ZrO2, HfO2, MgAl2O4, ZnAl2O4, ZnGa2O4, TiZn2O4, YAlO3, LaAlO3,LaGaO3, LaGaO3, NdGaO3, KTaO3, SrTiO3, Si, SiC. The Hartman-Perdok concept was used to estimate the atomic surface topology of the film/substrate interface. In conclusion, some recent experimental results will be discussed as well.