Although the corrosion behavior of metals under thin electrolyte layers (TELs) has been widely studied, little is understood about the electrode processes under these layers and even less so when exposed to a direct current (DC) electric field. This work shows that the open circuit potential (OCP) shifts negatively, the current density of oxygen reduction increases and initial hydrogen evolution potential shifts positively with enhancing the DC electric field intensity. The OCP shifts positively under the polarity reversal of DC electric field. The area covered with corrosion product decreases with increasing DC electric filed intensity. All these results indicate that the applied DC electric filed promotes the corrosion resistance of carbon steel. The synergistic effect of electric field on the electrode process of TELs has also been discussed in depth. (c) 2018 The Electrochemical Society.