Abstract: The potentiostat is key equipment of cathodic anticorrosion protection system to underground or underwater metallic structures, and owns more than 90% of all cathodic protection power supply in China. At present, several main techniques of potentiostat is the type of magnetic saturation amplifier, high power transistor, DC/DC converter and high-frequency switching inverter etc. This paper analyzes and summarizes the working principle, technical performance and problems of various potentiostat, and also introduces current technical situation and developing trends of cathodic protection power supply in China and foreign countries.