The results of analyzing the photoluminescence spectra of metamorphic In0.75Al0.25As/In0.05-0.8Al0.95-0.2As/GaAs heterostructures grown by molecular-beam epitaxy method are presented. In the spectra of low-temperature photoluminescence, three emission peaks have been detected, which correspond to carrier recombination in different areas of the structure. These include a part of the In0.75Al0.25As “virtual substrate” grown at high temperature, and the area of a triangular potential well formed by the meta-morphic buffer layer and the “virtual substrate”. Photoluminescence related to defects in the high-temperature part of the “virtual substrate” was also measured.