The paper presents a three-dimensional cellular automaton model of electrochemical oxidation of the carbon. The sample of the electro-conductive carbon black “Ketjenblack EC-600JD” consisting of granules of carbon is simulated. The electrochemical oxidation of the carbon granules occurs through a few successive stages. Parallel implementation of the three-dimensional cellular automaton model of carbon corrosion is developed. The efficiency and speedup of the parallel code are analyzed. The portions of surface carbon atoms and atoms with different degree of oxidation are computed by the parallel code. Based on the obtained values of atom portions the electrochemical capacity is calculated. The results of computer simulation are compared with the experimental data.