Heat exchangers, as the major equipment for forced heat exchange, are now widely utilized in all areas of life, however in real usage, corrosion failure can frequently occur and cause catastrophic mishaps. In this study, the composition of the corrosion products in the heat exchanger's head section was examined using XRF and XRD, and the corrosion of Q345D steel in the head section was examined using the dynamic potential polarization curve test method in conjunction with SEM under various CO2 and O2 partial pressure and temperature conditions. Fluent simulation software was also used to simulate the impact of erosion corrosion on the heat exchanger's head section. Results indicate that the main corrosion products in the regenerative heat exchanger E-303 are Fe3O4, with minor amounts of Fe2O3 and FeOOH; in terms of temperature, CO2 and O2, these three influencing factors on the heat exchanger head Q345D steel corrosion results, the temperature on the steel corrosion damage is significantly greater than the local corrosion caused by CO2 and O2, but when the temperature is higher than the solution boiling point of its corrosion in and out will occur. The flow rate scouring on the heat exchanger head high temperature inlet that is caused by the damage is much greater than the head low temperature outlet, corrosion damage is primarily concentrated in the lower inlet baffle, which is also consistent with the actual conditions of the site heat exchanger.