Cathodic protection technology refers to the electrochemically polarized metal structure that needs to be protected, so that its potential is shifted to negative direction.  A method of attaining the position of being in a cathodic, or protected, state in an ambient medium.  

Cathodic protection technology is a kind of electrochemical protection technology, the core of which is to move the metal potential to the negative direction in the electrolyte environment to achieve the corrosion free potential.