The results of the study of the electronic structure and optical properties of TmRhGe compound have been presented. Spin-polarized calculations of the band spectrum have been performed within the local electron density method with a correction for strong correlations in the 4f-shell of the rare-earth ion (LDA + U method). Optical constants have been measured using the ellipsometric method, and the spectral and electronic characteristics of the intermetallic compound under study have been determined in a wide wavelength range. Structural features of the experimental frequency dependence of the optical conductivity in the quantum light absorption region have been interpreted based on the calculated electron density of states.