The utility model discloses a storage tank buoyancy chamber steel plate with water-based nontoxic epoxy anticorrosive coatings, which is applied to anticorrosive construction in a closed space of an oil storage tank buoyancy chamber. The storage tank buoyancy chamber steel plate is characterized in that reserved welding sections are formed on the edges of the steel plate; the water-based nontoxic epoxy anticorrosive coatings are coated on the upper surface and the lower surface of the steel plate; the steel plate is 3m to 5m long, 0.8m to 1.5m wide and 3mm to 8mm thick; each reserved welding section is 100mm wide; and each water-based nontoxic epoxy anticorrosive coating is 0.08mm to 0.15mm wide. The storage tank buoyancy chamber steel plate has the effects of having properties of impact resistance, salt spray resistance and chemical medium resistance, and being capable of effectively prolonging the service life of the buoyancy chamber; and moreover, the steel plate has outstanding advantages in environment protection and security in anticorrosive construction in the closed space of the storage tank buoyancy chamber and the like, and can be applied to other anti-corrosion engineering with steel structures.