Abstract: The design methods and/or steps of cathodic protection, the selection of anodes, and the calculation of relative parameters in cathodic protection of metallic oil tank are introduced. Based on the design practices in cathodic protection for the newly-built tanks and old tanks, it is pointed out that taking the cathodic protection measure to control the corrosion for the newly-built tanks and reduce the damage for old tanks, as well as prolong tank's service life is of great importance.