The electronic structure of the rare-earth intermetallic La0.73Tb0.27Mn2Si2 is studied by resonant photoemission spectroscopy using synchrotron radiation, and its regularities of formation are established upon the partial replacement of lanthanum atoms by terbium. The dependence of the shape of the valence-band spectra on the photon energy near the absorption edges of the internal levels of manganese, lanthanum, and terbium is analyzed. The processes of the direct and two-stage generation of photoelectrons, and the elastic and inelastic decay channels of these states with the emission of high-energy electrons due to intra atomic Coulomb interaction are studied. The dominant mechanisms of the decay of the excited states of the components under study are determined from the shapes of the spectra. For rare-earth metals the elastic decay channel of the excited state is the most probable, while for manganese, it is inelastic, with the formation of a second hole in the valence band and the subsequent enhancement of photoemission. Upon the excitation of photoemission near the M5 absorption edges of rare-earth elements, the main contribution to the valence band comes from terbium 4 f states. In the case of the excitation of photoemission near the L3 absorption edge of manganese, the main contribution to the valence band is made by manganese 3d states; with an increase in the photon energy in the region after resonance, an Auger channel for the decay of the excited state arises in the form of a shift in the intensity maximum towards an increase in the binding energy. The features of the topography and magnetic domain structure of the La0.73Tb0.27Mn2Si2 surface are studied by atomic-force microscopy and magnetic-force microscopy at room temperature.