Different from electropolymerization and chemical polymerization. autocatalytic polymerization is a new method for synthesizing polyaniline films. In autocatalytic polymerization, aniline molecules were oxidized to polyaniline film by soluble oxygen on a platinum or palladium substrate. The reaction is initiated by catalysis of the substrate and then proceeds continuously with autocatalysis of the polyaniline film being deposited. The autocatalytic polymerization of aniline proceeds via an electrochemical mechanism that involves both anodic and cathodic half reactions at a single substrate, without the supply of electrolytic current.