Abstract: High temperature corrosion experiment of Super304H and Inconel625 alloy in high temperature CO2, together with oxidation weight increase method, scanning electron microscope and X-ray diffraction (XRD) were applied to study the corrosion behavior of the two heat resistant materials. The results showed that the oxidation kinetic of the materials followed the parabolic law under 750℃ CO2 and 750℃ CO2+SO2 environment, Inconel625 has a better corrosion resistant ability than Super304H, accompanied by less oxidation weight gain. Double-layered oxide scales consisted of nodular-typed Fe3O4 outer layer and FeCr2O4 inner layer formed after exposure 500 h in two environments and single Cr2O3 oxide scales. Whereas an stable and dense Cr-rich oxide layer of about 1 µm in thickness grew on Inconel625, implying that the Cr content plays a crucial role to improve the alloy corrosion resistance in high temperature CO2 environment. High temperature CO2 doping with SO2 has the effect of inhibiting carburization during the formation of Cr2O3, and has the effect of accelerating corrosion and carburization for iron oxide.