Dry bacteriorhodopsin (BR) film was fabricated into sandwich photocell and has differential photocurrent response to rectangular light pulse. And rectification was observed in the dry photocell of indium-tin oxide/BR film/Parafilm/stainless steel, but not of the steel/BR film/Parafilm/ ITO. This is an evidence of electrode-mediated rectification. Measurement of equilibrium potential suggests that the working electrode/BR film interface have different property from that of its counter electrode/Parafilm/BR film interface. The interfacial effect of the electrodes may dominate over that of the orientation of BR. Polarities of acid or base induced transient current confirmed the presence of rectification behavior of the electrode. The results will help to understand the mechanism of differential response of BR film.