Soil organic carbon sink is an important part of ecosystem carbon sinks under the strategic requirement of "carbon peak and carbon neutralization". The capacity of soil carbon storage and conduction of soil organic carbon sink accounting have increasingly become the research hotspots on soil organic carbon sink. This paper reviews the domestic and foreign research results of soil organic carbon sink and accounting. On the basis of relevant research results, three research contents are proposed around soil carbon sink accountinganalyzes the concept and connotation of soil organic carbon sink, and puts forward the characterization index and acquisition method of soil organic carbon sink with stable organic carbon.From the perspective of soil genesis, the concept of soil carbon sink threshold is proposed. The content of organic carbon in soil will eventually reach a dynamic equilibrium with decomposition and transformation.At this time, the stable organic carbon content value is about a constant, which is the storage capacity of the stable carbon pool. Under specific soil forming factors, the calculated value of the carbon pool will not exceed the normal value at equilibrium. Objectively, it is reflected in the content of stable organic matter of different soil types under natural conditions under non-human interference. Referring to the theory of soil organic matter balance, a quantitative method for soil carbon sequestration accounting has been proposed, which provided a set of technical approaches for measuring and accounting soil carbon sink. In the next step, the accounting of soil organic carbon sinks should be based on scientific research to build consensus from multiple perspectives, formulate carbon sink accounting standards, and determine operable, repeatable and reproducible soil organic carbon sink accounting techniques and methods at different scales.