Photoluminescence, cathodoluminescence and light absorption spectra of CaCu(Si2O5)2 have been explored in the spectral range from ultraviolet to near infrared. The luminescence and light absorption spectral bands have been analyzed to determine their constituent peaks. In photoluminescence spectra, the main very intense luminescence band reaching maximum around the quantum energy of 1.42 eV has been found to be composed of six spectral components with the strongest one peaked near 1.41 eV. In cathodoluminescence, only three of six lines have been found to constitute this band, with the strongest one peaking also at 1.41 eV. Besides, two much weaker bands of cathodoluminescence—a narrower one peaked at about 2.2 eV and a broad one spreading from the blue–green spectral region to the near UV range—have been detected in the visible and UV spectral ranges at T=300 and 80 K and the e-beam energies of 10, 15 and 30 keV. The shape and peak composition of the latter band depend on the e-beam energy and sample temperature. The origin of the derived spectral peaks is discussed.