Chemically oxidative polymerization of aniline and o-anisidine with 5 molar rations was performed using ammonium persulphate as an oxidant in HCl medium at 0-4 0C.It was observed that the copolymers were not regularly dependent on the monomer ration for yield and intrinsic viscosity.The resulting copolymers were characterized by Fourier transform IR Spectroscopy,1H NMR Spectroscopy and electrical conductivity.The results showed that the actual content of the o-anisidine unit in the copolymers was much higher than the feed content of the o-anisidine unit. Given the same reaction conditions, o-anisidine showed a larger tendency toward homopolymerization rather than toward copolymerization with aniline. The electrical conductivity of the copolymers is strongly depends on the amount of aniline incorporated and it decreases with increasing the o-anisidine content in copolymer which may lowers the structural regularity of copolymer. It is suggested from the temperature dependence of electrical conductivity that the electrical conduction mechanism of copolymer is polaron hopping conduction similar to that of homopolymers. The application of copolymer as anion exchange resin and acid-base indicator are presented.