It has been shown experimentally for the first time that diffusion of cesium n rhenium takes place at irradiation of atoms flux heated up to Т ≤ 1800 K -C. Analysis of thermal desorption spectra showed that cesium forms two high-temperature phases during adsorption of cesium on graphite monolayer in rhenium heated up to 1800 K. The first, intercalated phase starts filling immediately and grows up to maximum concentration. The second, diffusion phase appears with slight delay and grows incessantly during adsorption. It is for the first time that the Fick Equation has been applied for such kind of diffusion. Correspondences and average displacement L = f(Т,t) have been obtained at diffusion of surface cesium in rhenium in the interval of temperatures 1600 K < Т < 2200 K. At conditions of ν = 5 × 10¹³ cm^-2·s^-1, U = +2000 V, T = 1700 K, effectiveness of cesium diffusion δ_Cs in the system of Re(1010)-C was identified with application of suggested methods, which showed δ_Cs = 0.45. Activation energies of Сs atoms diffusion in rhenium from rhenium were found and values Е_1p = 5.65 ± 0.05 eV and Е_p1 = 5.85 ± 0.05 eV were obtained respectively. Effect of electrical field on intercalation and cesium diffusion in Re-C was observed.