A novel multilayer film is assembled from highly sulfonated polyaniline (SPAN) and diazoresin (DR) in aqueous solution via electrostatic attraction. Under UV irradiation, following the decomposition of diazonium group between the adjacent interfaces of the multilayer, the ionic bonds of the self-assembled film convert to covalent bonds and the film becomes very stable toward polar solvent or electrolyte solutions. Thus the photoelectric conversion property of highly sulfonated polyaniline containing film can be measured in conventional three-electrode photoelectrochemical cell, and a 0.5 mol/L KCI solution is used as the supporting electrolyte. The photocurrent spectroscopy responses coincide with the absorption spectrum of the self-assembly film, which means that the SPAN/DRfilm is responsible for the photocurrent generation, and the effects of bias voltage and photo intensity to the self-assembly film were also investigated in this article.