Abstract: This paper describes the experimentation and application of Al-Zn-In-Cd anodes.The composition of anode (Al-(2.5～4.5) Zn-(0.02～0.03) In (～0.01)Cd) is determined by laboratory and field tests,and appropriate emphirical formula for cathodic protection design calculation has been selected and checked.From actual use in the protection of offshore structures such as platform etc.,it has been proved that this kind of anode has stable and reliable electrochemical properties,containing impurities of Fe<0.16%,Si<0.13% and Cu<0.005%.The steel structures of offshore platforms can be well protected when properly designed and installed.