Abstract: In order to optimize the injection parameters for CO₂ saline aquifer storage in East China Sea, Pipesim software was used to establish a temperature and pressure calculation model of CO₂ injection wells. The influence law of injection pressure, injection temperature, injection velocity, fluid composition and well type on wellbore temperature and pressure distribution was analyzed. The results show that the change of injection pressure has a significant impact on the wellbore pressure distribution, while changing the injection temperature and injection rate has a considerable impact on the wellbore temperature distribution. Variations in the injected fluid component have a relatively minor effect on wellbore temperature and pressure. The well type has a greater impact on wellbore temperature. The phase change of CO₂ in wellbore do not cause abrupt changes in temperature and pressure. Based on these findings, a method for optimizing the injection parameters of CO₂ was proposed. Using this method, the optimal injection parameters that meet the annual CO₂ injection volume requirement of 200,000 tons were evaluated as follows: injection pressure of 10 MPa and injection temperature of 20 ℃. This method can provide technical guidance for subsequent engineering design.