Disclosed herein is a method of preventing corrosion degradation in a defective region including an expansion transition region and/or an expansion region of a heat transfer tube of a steam generator in a nuclear power plant by using nickel (Ni) plating or nickel (Ni) alloy plating. The method can prevent various types of corrosion damage, such as pitting corrosion, abrasion, stress corrosion cracking, lead-induced stress corrosion cracking and the like, occurring during the operation of the steam generator, and particularly, pitting corrosion or primary and secondary stress corrosion cracking, so that the life span of the steam generator is increased, maintenance costs are reduced, and the operation rate of a nuclear power plant is increased, with the result that the unit cost of the production of electric power can be decreased, thereby improving economic efficiency. Further, the method can be usefully used to prevent the corrosion damage of parts and equipment of nuclear, hydroelectric or thermoelectric power plants or of petrochemical plants, and that of industrial and machine parts and equipment, and parts and equipment in a defense industry.