Carbon capture, utilization, and storage (CCUS) technologies are crucial for reducing CO2 emissions. Currently, subsea CO2 storage is considered a highly feasible CCUS method. With the development of marine CCUS projects, impact loads from ship anchoring and marine debris, combined with internal corrosion defects in CO2 transport pipelines, significantly increase the risk of pipeline failure. This represents a major challenge for offshore SCCO2 pipelines. To investigate the stress–strain response of corroded pipelines under impact loads, a pipeline model with corrosion defects under rockfall impact conditions was established using ABAQUS 2014 finite element software. By varying factors such as the rock mass, impact velocity, drop point, and defect area, a single-variable analysis was conducted to explore the dynamic response of the pipeline. The results indicate that the rock mass and impact velocity are the key factors affecting pipeline stress, while the drop point and defect area have minimal impacts. Additionally, when the pipeline reaches yield failure, the effects of these factors become negligible.