海上二氧化碳（CO₂）地质封存是中国应对滨海地区温室气体排放的重要举措，是实现“碳达峰、碳中和”目标不可或缺的关键技术。中国沿海地区工业发达、碳源丰富，近海盆地具有良好的储盖层物性和圈闭特征，封存潜力巨大，目前中国首个海上CO₂地质封存示范工程已在南海珠江口盆地正式启动。CO₂监测作为CCUS技术的重要组成部分，贯穿CO₂地质封存的全生命周期，是确保封存工程安全性和合理性的必要手段。然而，中国海上CO₂地质封存技术处于起步阶段，海上监测任务颇具挑战。文章回顾了国际上海上CO₂地质封存的相关代表性研究工作以及示范项目案例，对监测指标、技术、监测方案等进行分析，提出海上CO₂地质封存监测技术筛选优化方法和监测建议，旨在为中国海上CO₂地质封存示范项目的开展提供参考依据。

Marine carbon dioxide (CO₂) storage is an important means to cope with greenhouse gas emissions in China’s coastal areas, and is an indispensable key technology to achieve the goal of “emission peak and carbon neutrality”. The coastal areas of China are industrially developed and rich in carbon sources. Owing to the good physical properties and reservoirs and trap characteristics, offshore basins have huge storage potential. At present, the first marine demonstration project of China has been officially launched in the Pearl River Estuary Basin in the South China Sea. As an important part of CCUS technology, CO₂ monitoring runs through the whole life cycle of CO₂ geological storage and is a necessary method to ensure the safety and rationality of storage works. However, China’s CO₂ marine storage technology is in its infancy, and the task of marine storage monitoring is quite challenging. For this reason, this paper reviews the relevant representative research and demonstration project cases of international CO₂ marine storages, summarizes the monitoring indicators, technologies and schemes, and puts forward the screening and optimization methods of monitoring CO₂ marine storage and suggestions for monitoring technology. The outcome of this study provides a reference for the development of CO₂ marine storage demonstration projects in China.