This project is one of the national key scientific and technological project “Major equipment and related technology of deep-water marine structure”. Adopt the “impressed current and sacrificial anode" cathodic protection technology for underwater surface of the deep-water semi-submersible lifting pipelaying barge. Improve the level of corrosion protection, monitoring and control of the main structure in its whole life cycle and realize the optimal design of cathodic protection system based on the numerical simulation. This project mainly focuses the studies on (1) anti-corrosion coating systems research on the deep-water semi-submersible lifting pipelaying barge (2) research on the whole life cycle design of “impressed current and sacrificial anode" cathodic protection system (3) research on control method of the impressed current cathodic protection system (4) research on the corrosion monitoring and control method integration technology and equipment development (5) research on the corrosion monitoring and control system test.