Abstract: The conductive polyanilinecobaltosic oxide (PANICo3O4) composites were synthesized by insitu polymerization. The conductive composites with different contents of Co3O4 were studied. The structure and thermal stability of obtained composites were characterized by Fouriertransform infrared spectra (FT-IR), X-ray diffraction (XRD), thermogravimetry (TGA) and differential thermogravimetric (DTG). The electrochemical characterization of composites were investigated in copper sulfate electrolyte solution. Results showed that the PANICo3O4 composites had the maximum conductivity of 4.56 S/cm under the condition of mCo3O4:mAn=0.05, and a strong interaction existed at the interface of PANI and Co3O4. Thermal stability of PANICo3O4 composite was higher than that of PANI. The catalytic activity and corrosion resistance of PANI with defined amount of Co3O4 in copper sulfate electrolyte solution could be improved.