Abstract: The ocean is the largest carbon sink on Earth and plays a critical role in mitigating global climate change. Accelerating research on the classification of oceanic carbon sinks is a vital measure to enhance scientific understanding of oceanic carbon sink classification, promote the restoration of marine ecosystems, facilitate carbon sink market transactions, and achieve dual carbon goals. This study, starting from an integrated perspective of “development-protection-carbon sink”, systematically reviews the current challenges in the classification of oceanic carbon sinks, and is dedicated to constructing a multi-level, multi-dimensional framework for the classification of oceanic carbon sinks tailored to China’s unique marine ecosystems. It aims to provide an in-depth analysis of the composition and characteristics of oceanic carbon sinks, specific to China’s unique marine ecosystems, by refining aspects such as the formation properties, mechanisms of action, spatial distribution, types of ecosystems, categories of carbon stocks, and species differences. This endeavor seeks to reveal the formation mechanisms, trends, and potential of oceanic carbon sinks, thereby offering a scientific management framework for monitoring, assessing, and managing oceanic carbon sinks and providing practical guidance for the classification and zoning of oceanic carbon sinks.