The main objective was to study the anticorrosion performance of poly(o-toluidine)/nano ZrO2/epoxy composite coating. Poly(o-toluidine)/nano ZrO2 composite was prepared by in situ polymerization of o-toluidine monomer in the presence of nano ZrO2 particles. Fourier transformation infrared spectroscopy (FT-IR), UV-visible spectroscopy (UV-vis), X-ray diffraction (XRD), Scanning electron microscopy (SEM), and Thermogravimetric analysis (TGA) were used to characterize the composition and structure of the composite. Poly(o-toluidine)/nano ZrO2 composite was mixed with epoxy resin through a solution blending method and the three components poly(o-toluidine)/nano ZrO2/epoxy composite coating was coated onto the surface of steel sample by the brush coating method. The anticorrosion performance of poly(o-toluidine)/nano ZrO2/epoxy composite coating on steel sample was studied by polarization curve and electrochemical impendence spectroscopy in 3.5% NaCl solution as corrosion environment and also compared with that of poly(o-toluidine)/epoxy composite coating and pure epoxy coating. It was observed that the composite coating containing poly(o-toluidine)/nano ZrO2 composite has got higher corrosion protection ability than that of poly(o-toluidine). The electrochemical measurement results demonstrated that poly(o-toluidine) ifllers improve the electrochemical anticorrosion performance of epoxy coating and the addition of nano ZrO2 particles increases the tortuosity of the diffusion pathway of corrosive substances.