The topcoat is an aliphatic acrylic polyurethane topcoat. The paint has excellent resistance to atmospheric and ultraviolet rays. Because aliphatic isocyanates have characteristics such as yellowing resistance, aging resistance, and temperature resistance, they are coated after crosslinking to form a film. Layer has excellent physical and mechanical properties and chemical resistance to atmospheric ultraviolet and chemical media, the paint film is not easy to yellowing and chalking, adhesion, physical and mechanical properties are good, weather resistance is very strong, at the same time, it has excellent recoatability and matching The external surface of the floating floating crude oil storage tank, the inner surface that needs to be anticorrosive and the surface of the internal components of the tank are sprayed to remove rust, and it is required to reach the Sa2.5 level in SY / T0407-1997 "Specifications for Steel Surface Pretreatment before Painting". The spraying operation should be performed in the order of filling the top, then the tank wall, and the bottom of the tank. The depth of the anchor pattern is preferably 40 ~ 80 μm. The surface treatment of the accessories in the tank should be the same as the inner wall of the tank.