Abstract: In accordance with the service conditions and relevant performance requirements for the casing，the HS110-13Cr anti-CO₂ corrosion casing is developed. In the development process focused are the design of the chemical composition of the steel as made for the said casing and research on the heat treatment process for it. And the thermodynamic software is used to calculate the strengths and impact toughness curves of the said steel at different tempering temperatures. It is revealed via the research that the said impact energy is going down dramatically at specified temperature. And the fractures of the impact test specimen of the steel are observed with the SEM，finding that the fracture of the specimen as tempered at 570 ℃ is a kind of brittle intergranular fracture. Accordingly when using relevant heat treatment process，it is necessary to avoid the tempering brittle zone. The performance of the above mentioned product as developed and manufactured is satisfactory to the customer requirements. Furthermore the casing is passed the corrosion evaluation，and then is successfully used in a certain domestic oil field，having met the applicable requirements for the CO₂ service environment.