Abstract: Marine aquaculture may be one of the effective ways to achieve the goal of carbon neutrality in China. The shellfish and seaweed aquaculture is an important part of the marine aquaculture by sequestrating carbon from the seawater (harvest) and sealing it into the sediments in the form of shells, and thus making an effective carbon sink in marine aquaculture. As an important aquaculture country, China has a great potential of carbon sequestration in future. However, there is not a official protocol in the calculation, evaluation, and monitoring of carbon sink in the field of shellfish and seaweed aquaculture at present. Also, it is not clear on the definition of the boundary of carbon sink, such as storage life and turnover year. This study presents the potential of carbon sequestration and suggests combing the fixing carbon and releasing carbon via respiration when calculating the carbon potential during mariculture. We raise the issues of carbon sink calculation and point out that the weighting method is not enough to reflect the reality of carbon sink potential. We suggest that figuring out the boundary of carbon sink (e.g., by using the definition of long/short carbon period) should be the first step to constrain the carbon sink potential of mariculture. Finally, we discuss the necessity in the evaluation of the warming potential in shellfish and seaweed aquaculture and propose taking considerations of the role of non-carbon dioxide greenhouse gases in the carbon sink calculation.