Abstract: In this work,the corrosion state of the Jiyuan warship sank the deep-sea bottom for 84 years has been investigated. The type of the steel used for the main parts of the warship, the metallogic organization and chemical composition of the steel, the corrosion type of each kind of steel and its reason has been determined. The law and the characteristics of the deep-sea corrosion have been preliminarily revealed.