Abstract: The offshore geological storage and utilization technology for carbon dioxide （CO₂） is crucial for China to achieving the national dual carbon goals. However, the technological development pathways and policy roadmap remain unclear. This study develops a multi-dimensional assessment framework, covering technological, economic and contribution-based aspects, which is tailored to the characteristics of offshore CO₂ geological storage in China. The framework systematically evaluates the status, storage potential, and emission reduction contribution of CO₂ storage in offshore saline aquifers and oil fields towards realizing these dual carbon objectives, while proposing corresponding technological development pathways. The results indicate that the technology readiness level of offshore CO₂ storage technologies in saline aquifers and oil fields in China ranges between levels 3 and 4. This highlights a considerable gap before commercial demonstration and large-scale application can be achieved. The current annual emission reductions remain at only 300 thousand tons, constrained by high costs, key technological bottlenecks, and insufficient policy support. We propose a phased development pathway characterized by demonstration-led scale promotion and cluster deployment. In the short term, efforts should focus on overcoming core technical barriers and integrating industrial chains. In the medium to long term, priorities should shift towards scaled application and institutional development. As scale expands, technological advances and systemic improvements, the cost of offshore CO₂ storage is projected to decline to 50~150 RMB/tonCO₂ by 2060, with an annual storage capacity of 200−300 million tons. This would contribute 15−20% of the cumulative carbon neutrality effort in China, significantly enhancing emission reduction capabilities while also promoting innovation in marine technology and climate governance.