Abstract: The corrosion behavior of 304NG stainless steel was investigated in supercritical water (SCW) at 550, 600 and 650 ℃. The SEM, EDS and XRD were used to analyze the corrosion morphology, structure and chemical composition of oxide film. The experiment results show that the oxidation of 304NG stainless steel approximately follows power function growth kinetics after exposure to supercritical water for 1 000 h, while the weight gain decreases drastically at 650 ℃. The possible mechanism of the anomalous temperature dependence of oxidation kinetics is ascribed to the rapid diffusion of Cr at higher temperature, maintaining protectiveness of oxide film on the sample surface, and finally resulting in the decrease of the nodular corrosions.