Subsea production pipelines face increased failure in the complex ocean environments, corrosion is one of the main causes of pipeline failure. This paper focuses on the external corrosion damage mechanism of deepwater production system pipelines subject to different kinds of impact loading in the service process. By introducing electrochemical parametric equations that consider elastic-plastic deformation, stress field and electric field are adequately combined, and the external corrosion damage model of the pipeline is proposed considering the effects of the thermal-force-electrical multi-field coupling. Such model is intended to capture the corrosion electrochemical reaction behavior of a defective pipeline under the influence of various risk factors, including defect size, internal temperature, and axial displacement. The degradation mechanism-driven corrosion damage is summarized by considering the stress at the center of the pipeline defect, the anode current density, the corrosion rate, the amount of corrosion degradation, and the maximum safe operating pressure of the pipeline under different working conditions. The interaction of multi-field coupling in the corrosion damage to the pipeline is demonstrated by a case study. The results indicate that a larger defect size and a greater increase in the temperature inside the pipe will lead to higher stress on the defect, resulting in more serious corrosion damage. Plastic deformation can significantly increase the electrochemical corrosion activity of the pipe to exacerbate the corrosion damage to the pipe, providing support for pipeline risk assessment and integrity management.