As it is difficult to repair the damage of epoxy coated steel bar in marine engineering structures，this paper uses the cathodic protection technology combining sacrificial anode and conductive mortar to study the change trend of conductive mortar resistivity along with age.It studies the cathodic protection effects of the sacrificial anode on epoxy coated steel bars with different damage rates in the conductive mortar，including the protection potential，emission current，and steel bar apparent changes.In addition，the service life of the sacrificial anode is evaluated based on the data of its state change.The results show that the sacrificial anode and conductive mortar can protect the damaged epoxy coated steel bars，and the lower damage rate of the steel bars is accompanied by the shorter time needed for the protection current in the system to reach equilibrium.The sacrificial anode mortar can protect the epoxy coated steel bars with a breakage rate less than 10% for 53 years.