Abstract: Cathodic protection systems of nuclear power plant are mainly used to protect sea water related equipment such as drum net, grille, condenser water chamber and cold source pipeline. The typical faults were analyzed during the check and reparation of cathodic protection system in refueling overhaul of nuclear power plant. And the maintenance strategy of cathodic protection system was put forward combining the preventive maintenance and management program with the system operation and maintenance procedures of nuclear power plant, to ensure normal and stable operation of cathodic protection system during plant commercial operation and to prevent the corrosion of the protected equipment.