The mechanisms of creation of electron-hole trapping centers in LiKSO4 have been investigated by the
methods of vacuum and thermal activation spectroscopy. It is shown that electron-hole trapping centers are formed during the trapping of electrons by anionic complexes and localization of a hole in the lattice in the form of the radical SO−4. The appearance of phosphorescence at 3.0-3.1 eV, 2.6-2.7 eV and 2.3-2.4 eV confirms the creation of electron-hole trap centers.