We performed the oxidation of austenitic stainless steel AISI SAE 317, to 700 and 750°C in an atmosphere with 100% water vapor, to evaluate the corrosion behavior. We obtain the gain mass and the oxides films were analyzed by Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD) to observe the oxides scales are formed. We are discussing the possible mechanism of oxidation in steam environmental. The mechanism of attack at 750°C is similar to 700°C, although the oxidation rate is higher, because the diffusion of alloying elements and oxidation reactions are faster.