To research the corrosion resistance of normal carbon steel P110, 3Cr, martensitic stainless steel 13Cr and super-martensitic stainless steel HP2-13Cr in simulated supercritical CO2 environment. Methods The corrosive environment of high temperature/ high pressure/CO2 enriched and Cl– contained oil well was simulated. The above four kinds of steels were tested by blade-hanging with a high temperature and high pressure reactor. Their characteristics of anti-general corrosion and corrosive pitting were analysed in the aspects of average corrosion rate, surface characteristics of samples after clearing the corrosion products, surface morphology, composition of corrosion products and corrosion mechanism using high class electric balance, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Results In the environment at 110 ℃ and containing 12 MPa partial pressure of CO2 and 16 542 mg/L Cl–, the average corrosion rate of P110 and 3Cr were 5.625 mm/a and 2.992 mm/a respectively. The corrosion rate of 13Cr was 0.155 mm/a and pitting corrosion occurred on its surface, the corrosion rate of HP2-13Cr was 0.003 mm/a and general corrosion occurred. HP2-13Cr met the using requirement in the corrosive environment. Conclusion In the above supercritical CO2 environment, the corrosion resistance of carbon steel P110 and 3Cr is low because no tight corrosion films containing rich Cr covered on their metal. The corrosion resistance of martensitic stainless steel 13Cr and super-martensitic stainless steel HP2-13Cr are better than the two former due to dense passivation film on the surface. However, the content difference of Ni and Mo contribute to significant difference in their resistance to general corrosion and corrosive pitting.