Abstract：Due to the characteristics of back silting in Tianjin Port, the sacrificial anodes on steel structures for some wharfs
（especially for old wharfs） are buried to different degree, causing the useful life and effect of the cathodic protection system of
sacrificial anodes to reduce, which affects the safety and service life of the whole wharf structure. To overcome the above problems，
a new cathodic protection method using Al-Zn-In-Si sacrificial anodes encased in composite material in sea mud area
was put forward and applied to actual project. The engineering practice shows that the protective results of the sacrificial anode
cathodic protection system are good and it has a positive meaning in cathodic protection of steel structures deeply buried in sea
mud in Tianjin Port.