A study has been made of the effect of local light irradiation and silver saturation on the contact photo-emf excitation spectrum of α-RbAg4I5superionic crystals at room temperature. It was found that irradiation with light having energies 2.75 eV and 2.92 eV causes color centers formation in the crystals. The possible nature of the bands in the photo-emf excitation spectrum is discussed. Time dependences of the photo-emf for the main excitation bands were measured at various illumination levels. A characteristic asymmetry of the relaxation curves governed by the excitation kinetics was observed at high illumination intensities. The estimation of the photon capture cross sections for the electronic transitions gives the values of the order of magnitude of 10−17cm2. The transient experiments have shown that the photocarrier lifetimes in the crystals are of the order of 1000 sec.