IGCC (Integrated coal gasification combined cycle) is an eco-friendly coal power plant technology. However, the corrosion of high-temperature material parts in the IGCC power plant ℃curs severely, limiting the operating temperature. Especially formation of sulfide, owing to H2S, SO2, SO3, made the scale highly sensitive to cracking and spalling. Therefore, it is necessary to study in the serious corrosion environment. In this study, high-temperature corrosion resistance and characteristics of Fe-9Cr-1Mo alloy were studied at 600-800 ℃ in air, (H2S/H2O)-mixed gas, (Bal. CO2/SO2/O2)-mixed gas condition up to 200 hours. Fe-9Cr-1Mo alloy is one of the heat-resistant alloy materials in power plants. The corroded test coupons were characterized by a scanning electron microscope (SEM), an X-ray diffractometer (XRD) with Cu-Kα radiation, and an electron probe micro-analyzer (EPMA).