A new effect of illumination on ionic conductivity and activation energy of migration of mobile Ag+ cations in RbAg4I5 superionic crystals has been detected and studied. Reversible changes in the structure of electronic centers caused by elastic strain around these centers. The effect of elastic deformation on the process of ionic transport and activation energy for diffusion of mobile silver cations has been studied. Photostimulated recovery of the ionic conductivity after its change due to preliminary illumination of a RbAg4I5 superionic crystal with light of wavelength lambda =430 nm has been detected. This recovery of the ionic conductivity is due to excitation of centers in complexes generated by previous illumination of tested samples.