We have investigated the photoisomerization using light irradiation 8A5H-DLPC mixture(1:1) LB film accumulated by monolayer on an ITO. We determined electrochemical measurement by using cyclic voltammetry with a three-electrode system. An Ag/AgCl reference electrode, a platinum wire counter electrode and LB film-coated ITO working electrode measured in NaClO4 solution at a variable concentration. The scan rate was 100 mV/s.