With the intensification of global warming, controlling CO₂ emissions has become a consensus within the international community. CCUS (Carbon Capture, Utilization, and Storage) technology is recognized as one of the critical pathways to achieve the dual carbon goals of 'carbon peaking and carbon neutrality'. Statistics indicate that coal-fired power plants in China contribute over 35% of the total CO₂ emissions. The amine-based CO₂ capture technology has been widely adopted due to its advantages of high absorption capacity and relatively low regeneration energy consumption. However, flue gas typically contains SO₂ in addition to CO₂. When SO₂ dissolves in amine solutions, it rapidly hydrolyzes to form HSO₃⁻ and SO₃²⁻. These sulfur-containing species exert a significant influence on the nucleation and growth processes of corrosion product films, triggering accelerated corrosion of carbon steel in equipment such as absorption towers and circulation pipelines. In this study, immersion experiments were conducted to investigate the influence of SO₂ on film evolution, as well as the organizational structure of the films at different stages. By employing techniques including weight loss testing, in situ electrochemistry, SEM,EDS, and XPS, this paper clarifies the structural characteristics, evolution, and corrosion behavior of corrosion products under SO₂-containing conditions, and elucidates the underlying mechanisms.