The low-temperature photoluminescence spectra of gamma-phase of RbAg4I5 crystal (T less than or equal to 122 K) exposed to the light irradiation with similar to 425 nm wavelength and X-ray irradiation at room temperature in superionic alpha-phase were investigated. Analyzing the behaviour of similar to 390 nm emission band influenced to the exposed irradiations, a mechanism for the low-temperature photoluminescence is proposed and discussed. XPS, AES and the low-temperature and room temperature UPS spectra of RbAg4I5 superionic crystal are subjected to preliminary investigation.