Abstract: The corrosion behaviors of 3Cr steel in simulative CNOOC CO₂ environment have been studied with a high-temperature and high-pressure reactor. Under the conditions that temperature was 60℃, CO₂ partial pressure was 1.5 MPa and the flow velocity of corrosive medium was 1 m/s, two kinds of 3Cr steel samples present severe uniform corrosion, the average corrosion rate of 3Cr steel are 3.85 mm/a and 3.24 mm/a respectively. The corrosion products of 3Cr steel in CO₂ environment have been analyzed by SEM and EDS. The result indicates that the products of 3Cr steel have two layers, the outer main structure is FeCO₃ with stacking loose and low adhesion, the inner layer is product film with enrichment Cr.