Due to the multifaceted factors influencing internal corrosion of deepwater subsea pipelines, current data falls short of meeting the requirements for implementing direct internal corrosion assessment (ICDA) technology. Furthermore, technical challenges arise from excavation verification difficulties caused by marine environmental limitations. This study aims to investigate the applicability of direct ICDA technology in deepwater subsea pipelines by enhancing existing ICDA technology and processes based on their unique characteristics. A suitable corrosion risk assessment method is developed through exploring technologies such as corrosion monitoring data analysis, corrosion simulation testing, and pipeline flow support simulation analysis. Concrete case analysis validates the effectiveness of this method in addressing the urgent need for assessing internal corrosion risks in deep-water sea pipes.