In simulating Changqing Sulige oilfield environment and importing CO₂, corrosion weight loss method was used to contrastive study the corrosion behavior of ordinary 3 Cr and carbon steel at high temperature high pressure and normal pressure and temperature conditions. The results show that in the simulating corrosion environment, the corrosion rate of 3 Cr steel and carbon steel at the normal temperature and pressure respectively is 0 . 118 mm / a and 0 . 408 mm / a, while the corrosion rate of carbon steel is three times than 3 Cr steel . When the temperature and pressure increase, the corrosion rate of 3 Cr steel is 1 . 59 mm / a, which is approximately same with the carbon steel of 1 . 54 mm / a.