Polyaniline/Ag/Ce (NO 3 ) 3 ternary composites were prepared by in situ polymerization in a poly (2-arcylamido-2-methylpropane sulfonic acid) aqueous solution. Fourier transform infrared spectroscopy and Ultraviolet-visible spectroscopy analyses indicated that Ce ions had a conjugated interaction with N, O of polyaniline (PANI), and poly (2-arcylamido-2-methylpropane sulfonic acid). By comparison with PANI and PANI binary composite, this ternary composite had a better thermal stability, a high conductivity (3.49 S/cm), a large capacitance, and a high electrochemical activity. Especially, the corrosion potential of this ternary composite can reach 2418 mV and the inhibition efficiency can be increased by 68.08%. This ternary porous composite has promising applications in capacitor, conductive materials, anticorrosion coating, and other related fields. V C 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2015, 132, 42785.