During the suspended shipping period of a domestic ship lock,corrosion situations of its miter gates are fully detected.The corrosion level evaluation and the reasons analyses of coating blistering and steel gate corrosion are conducted corresponding to the region divided on basis of the position of anti-corrosion coating on the miter gate,namely atmosphere zone,water level fluctuation zone and submerged zone,respectively.The results show that coating blistering is commonly presented on the miter gate of this ship lock and the corrosion below blistering layer became gradually prominent as the coating effective life approaches.The total area of coating damage regions is in the proportion of 6.5%-12.7% of the miter gates.In general,the damage and failure process of protection coating on the miter gate can be separated into three stages:blistering of organic coating,corrosion development of thermal spraying aluminum layer,consumption of aluminum layer acted as sacrificial anode to suppress local corrosion of steel substrate.Moreover,it is pointed out that a long-term anti-corrosion effect is difficult to be achieved with piecemeal coating repair.An alternative method with respect to prolonging the service life of miter gates,including overall maintenance of anti-corrosion coating and the application of cathodic protection is proposed in present work.