Abstract: Take the corrosion of tank roof as an example, the corrosion cause is analyzed. On the basis of conventional repair method, a safer and simpler repair technique of tank roof, the fiberglass cladding method, is developed. This method can be in-line adopted without any fire work. The original tank roof is taken as a mould, an non-metal tank roof is made and then adhered to the old one in short time. The repaired tank roof is proof of light weight, high strength, long service life and satisfactory insulating property.