Carbon Capture, Utilization and Storage (CCUS) technology is a key pathway to achieving carbon neutrality. However, the tubing corrosion induced by the CO₂ flooding and storage process seriously threatens oil well safety. To address the limitations of existing mechanistic models—namely poor adaptability to extreme CCUS operating conditions and inadequate characterization of the coupling mechanisms of key parameters—this study proposes an electrochemical-mechanism-based model for predicting CO₂ corrosion rates in tubing. The model incorporates a dual-temperature-zone (low/high) mechanistic framework and introduces the Arrhenius equation to dynamically adjust the synergistic mechanism between ferrous ion concentration and temperature. This significantly enhances prediction accuracy under complex CCUS environments. Validation using production wells in a CCUS demonstration area of an oilfield showed that the model achieves a mean relative error (MRE) of 0.23 and a root mean square error (RMSE) as low as 0.00067 mm/a, demonstrating high accuracy. This model provides a reliable tool for life-cycle tubing integrity management in CCUS systems, offering significant engineering value for reducing corrosion monitoring costs and ensuring storage safety.