Polyaniline has been electrodeposited on an AA 7075 alloy by a potentiostatic method, and its corrosion protection ability has been studied by Tafel polarization and electrochemical impedance spectroscopic techniques in 1% NaCl. A pure polyaniline film protects the aluminum alloy up to 70%. However, the corrosion resistance property of the polyaniline film has substantially increased to 90% by post-treatment in a cerium salt solution. X-ray photoelectron spectra studies have shown that the film formed due to the post-treatment of polyaniline with the AA 7075 alloy in the cerium salt solution is composed of both Ce3+ and Ce4+ oxides.