Caseplate corrosion is a key issue affecting and determining service life of large-scale crude oil storage tank. Crude oil itself is noncorrosive, however, water and certain corrosive medium are usually mixed up with oils during exploitation process. “Water sinks and oil floats” during long-term storage, corrosive sedimentary water deposits on the bottom of oil tank, hence the tank bottom has been immersing in sedimentary water for a long term. Chemical composition of the sedimentary water is complex, which contains plenty of chloride, sulfate and anaerobic microorganisms. The mediums expose the oil tank bottom to strong corrosive environment and cause continuous corrosion to oil tank baseplate. Meanwhile, shock and vibration of the floating roof tank column, liquid turbulence and crude oil pressure will accelerate corrosion failure of oil tank baseplate. Corrosion mechanism and failure derivation mechanism of the oil tank bottom were discussed in detail; corrosion forms of tank bottom in sedimentary water environment were analyzed, including electrochemical corrosion, erosion corrosion, stack corrosion, microbial corrosion and weld corrosion; development status of heavy-duty anti-corrosive coating was introduced, including epoxy, polyurethane, zinc rich primer, fluorocarbon coatings; heavy-duty anti-corrosive coating technologies adopted by oil tank protection were analyzed; finally future research directions of oil tank baseplate protection was presented.