Three austenitic Fe-Ni-Cr alloys (253MA,310 and 353MA) have been oxidized in static air at 850℃ with a deposit of 2mg/cm(superscript 2)sodium chloride (NaCl). The results showed that the initial reaction for the corrosion of alloys is oxychlorination, while the chlorine (Cl2) released from initial oxychlorination accelerated the corrosion by the cyclic chlorination/oxidation. The alloying element of nickel shows noble characteristic. The metal losses of alloys are related to the total depletion amounts of iron and chromium from the substrate. According to the evaluation of the corrosion resistance of alloys from the total depth of attack, the best performance is the 310 with medium nickel content.