We have been applied the conventional approach based on the molecular dynamics simulation to estimate the redox potential so far. In this study, we have focused the computational conditions in order to estimate standard redox potential by using the energy representation method: we calculate excess chemical potential increasing the number of solvent molecules and sampling data for the preparation of energy distribution functions. From these results, we have found that the computational value of the standard redox potential is close to the experimental value in the case of the system with larger number of solvent molecules unaffected by the behavior of counter-ion when we take a sufficient sampling data for the energy distribution functions.Selected Papers from the International Symposium on Computational Science - International Symposium on Computational Science Kanazawa University, Japa