Abstract: The influence of coating damage rate and position and controlled potential on the distribution of cathodic protection potential and curcent have been studied by scale modeling.The experimental results suggest that the protection current and potential distribution are not only related to the area of coating damage,but also related to the controlled of auxiliary anodes and reference electrodes.By optimizing the controlled of auxiliary anodes and reference electrodes,the hull can be well protected and the potential distribution homogeneous,even though the coating is 10% damaged.The design principles of cathodic protection parameters,such as the location of auxiliary anodes and reference electrodes and controlled potential,have been established.