Cathodic protection is a system of preventing corrosion by forcing all surfaces of a hull to be cathode by providing external anodes. A metal can be made cathodic by electrically connecting it to a more anodic metal within the electrolyte. Anodes of these metals corrode preferentially, the corrosion current of the anode achieving cathodic protection of the underwater hull to which they are connected. This paper presents a new current control algorithm for ICCP (Impressed Current Cathodic Protection) system. The anode of ICCP system is controlled by an external DC source with converter. The function of anode is to conduct the protective current into seawater. The DC source is generally obtained from main power system that contains a transformer, converter and etc. The proposed algorithm can operate AC-DC converter with current link. This algorithm includes the harmonic suppression control strategy and the optimum protection strategy and has tried to test the requirement current density for protection, the influence of voltage, the protection potential. Also, the properties of ICCP protected hull of ship in seawater are evaluated.