Abstract: The corrosion behaviors of four typical materials in nitrogen protection atmosphere were studied in the simulated wet environment. The corrosion rate, corrosion appearance and the composition of corrosion products were investigated through weight-loss method profilometry and X-Ray diffraction (XRD), respectively. The results show that, in the gas phase, the trend of corrosion rate for two kinds of carbon steel decrease followed by a steady increase with the increasing of oxygen content; The Cr5Mo and 304 stainless steel both maintain stably at a low level. In the liquid phase, the corrosion rates of carbon steel and chromium-molybdenum steel increase obviously when oxygen content reaches to 1.0%. There is small difference of material corrosion rates when the oxygen content changes in the range of 0.5%~1.0% in both gas and liquid phase. The corrosion characteristics of carbon steel and chromium-molybdenum steel are basically the same. The corrosion products mainly consist of γ-FeOOH and Fe3O4, with metal ulcerated and etched. The 304 stainless steel still maintains the metallic luster and has no obvious corrosion.