The total amount of carbon emissions and the temperature increase limit proposed by the Stern Report warns us that it is urgent to establish an effective “negative emission” mechanism while reducing carbon emissions. Since the concept of “blue carbon” was proposed by the United Nations，research on ocean carbon sinks has always been a field of academic concern. This paper takes ocean carbon sink as the research object，analyzes the role and significance of ocean carbon sink to achieve carbon neutrality on the basis of reviewing relevant research literature，and puts forward the logic and key points of establishing the theoretical framework of ocean carbon sink as well as policy suggestions related to the development of ocean carbon sink. This paper proposes that the accounting and pricing of marine carbon sinks should focus on the economic activities of the main carbon sinks. By establishing a comprehensive demonstration area for marine carbon sinks，exploring the voluntary emission reduction market and investment and financing mechanisms，it is imperative to accelerate the implementation of marine carbon trading.