Abstract: With the acceleration of the pace of domestic green and low-carbon transformation, the offshore oil and gas field CCUS project is getting more and more attention from oil and gas field development workers because it can achieve permanent CO₂ injection and increase storage and production through CO₂ flooding. Due to limited area of offshore platforms, high cost of well repair operations, and the characteristics of multi-layered development, offshore CO₂ flooding projects have put forward new requirements for injection string. CO₂ injection string suitable for offshore oil and gas fields should be developed based on the development characteristics of these fields. This paper systematically reviews the development history and technology of CO₂ flooding injection string in land oilfield, analyzes the requirements and technical difficulties of offshore injection string, and optimizes the offshore CO₂ injection string from the two aspects of underground flow measurement and string safety. The development direction and key contents of CO₂ injection string technology are proposed to better support the rapid development of offshore CO₂ flooding business.