Since the Fukushima accident, it has been recognized that a hydrogen-related explosion is one of the major concerns regarding reactor safety during the high-temperature oxidation of zirconium alloys. To decrease the high-temperature oxidation rate of zirconium-based alloy, a coating technology for the zirconium alloy surface was considered. The selection of coating materials was based on the neutron cross-section, thermal conductivity, thermal expansion, melting point, phase transformation behavior, and high-temperature oxidation rate. After consideration of these factors, silicon was selected as a coating material for the first surface coating of zirconium-based alloy. A plasma spray and laser beam scanning were selected for the coating method, as both can be applied to a long tube shape without high-vacuum and high-temperature environments during the coating process. After Si-coated samples on Zircaloy-4 sheet had been prepared via plasma spray and combined plasma spray–laser beam scanning treatments, the samples were tested in a high-temperature steam environment at 1200°C for 2000 s. The adhesion property of the Si-coated layer prepared via plasma spray was insufficient for the high-temperature application, whereas the stability of the Si-coated layer prepared with both plasma spray and laser beam scanning treatments was maintained without peeling after a high-temperature oxidation test. A very thin oxide layer, which was a few micrometers in thickness, was formed on the Si-coated surface, whereas a ZrO₂ layer 110 μm in thickness was observed on the Zircaloy-4 surface. From this result, it was determined that the Si-coated layer successfully acted as corrosion barrier layer to resist the high-temperature oxidation of zirconium-based alloy.