A series of copolymers were synthesized by chemically oxidative polymerization of pyrrole (PY) and o-anisidine (AS) in acidic aqueous medium. The yield, intrinsic viscosity, and solubility of the copolymers were studied by changing the monomer molar ratio, initial polymerization temperature, oxidant, ratio of monomer over oxidant, acidic medium, and adding dodecylbenzene sulfonate. As prepared PY/AS copolymer powder, was characterized by FT-IR, UV-Vis, H-1 NMR, DSC, and TG techniques. The results showed that the oxidative polymerization from PY and o-anisidine is exothermic and the resulting copolymers exhibit an enhanced solubility in most of the organic solvents as compared with polypyrrole. The polymer obtained by the oxidative polymerization is a real copolymer containing pyrole and o-anisidine units. The PY molar content calculated based on the H-1 NMR spectra is slightly lower than feed PY content when feed PY content is lower than 30 mol%. The thermostability of the PY/AS copolymer increases with increasing PY unit content.