Cr electroplated Fe-18Cr-12Ni steels were corroded at 600-800oC to 30hr in (N2-1%H2S-H2O)-mixed gas condition, and their sulfidation characteristics were studied. Un-electroplated Fe-18Cr-12Ni steels corroded rapidly, forming outer FeS scales and inner FeS, Fe,Cr-(S,O)-mixed scales. The high growth rate of FeS impeded the formation of a continuous, protective Cr-rich oxide. Electroplated Fe-18Cr-12Ni steels corroded slower than un-electroplated Fe-18Cr-12Ni steels, because of Cr coated layer. Electroplated Fe-18Cr-12Ni steels formed much thinner scales, which consisted primarily of Cr2O3, Cr2S3 scales indicating that both sulfidation and oxidation occurred simultaneously. Cr2O3 oxide effectively provided corrosion resistance. Electroplated Fe-18Cr-12Ni steels corrosion resistance increased with increasing the Cr content. During sulfidation, it also displayed good corrosion resistance at 600oC, but it suffered from massive weight loss above 800oC.