The early corrosion behavior of low carbon 9Cr-ODS steel in 500 °C oxygen-saturated LBE was investigated. The thickness of the oxide film was found to increase with the duration of corrosion. Results from Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and the Shanghai Synchrotron Radiation Facility (SSRF) indicate that the oxide layer on 9Cr-ODS steel is multilayered, consisting of a (Fe, Cr)3O4 spinel inner layer, a nanocrystalline transition layer rich in Cr and Mn but poor in Fe, and an Fe3O4 outer layer. The corrosion mechanism of low carbon 9Cr-ODS steel in liquid LBE is discussed.