One of the main problems of stainless steel is its poor pitting corrosion resistance in the aggressive environment containing Cl-, such as seawater. In this paper we investigated the corrosion behavior of the 316 stainless steel coated by cerium oxide nanocoating prepared by sol-gel process. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were used to study the corrosion behavior of cerium oxide nanocoatings in 3.5% NaCI solution. The microstructure of the cerium oxide was examined by scanning electron microscopy (SEM) and the formed phases was identified by X-ray diffraction (XRD). The pitting corrosion resistance of the cerium oxide nanocoating was found to be improved after heat treatment of the cerium oxide nanocoating at 300~C for 30 rain.