Poly(aniline-co-o-anthranilic acid) (PAAA) and photosensitive diazoresin (DR) in aqueous solution were self-assembled into multilayer ultrathin film through electrostatic interaction. Under UV irradiation, following the decomposition of the diazonium group between bilayers, the ionic bond of the self-assembly film converts into a covalent bond, and the film becomes very stable toward polar solvent and strong electrolyte solution. Thus the photocurrent generation was studied in a conventional photoelectrochemical cell with 0.5 M KCI solution as supporting electrolyte. An action spectrum of the photocurrent generation is coincident with the absorption spectrum of the DR/PAAA self-assembly film on the ITO glass electrode, indicating that the polyaniline containing film is responsible for the generation of the observed photocurrent.