Abstract: Pneumatic, hydraulic devices, various valves and other motion components are widely used in almost all marine equipment, such as military and civilian ships, submarines, offshore platform. Sea water itself is a strong corrosive medium. The waves, tides and currents generate low-frequency reciprocating stress and impact on the metal components. In addition, marine microorganisms, adherent organisms and their metabolites all directly or indirectly accelerate the corrosion process. Compared with the land environment, the service life of the motion components in the marine environment is significantly reduced, which seriously endangers the service safety of marine equipment. Therefore, it is necessary to repair or replace the failed parts and protective coatings when the ship is regularly maintained. The economic, green and convenient surface protection technology has attracted much attention in shipyards. Here is introduced the application of surface protection technologies such as thermal spraying, laser cladding and chemical conversion in the field of ship maintenance at home and abroad in recent years, and put for ward several problems that need to be solved urgently in ship maintenance.