Ocean is the biggest carbon sink in the world. The total carbon load of the ocean is 39×10¹²t, which is 93% of total global carbon load, and about 53 times of carbon load of the atmosphere. Carbon in the ocean will either join in the biogeochemical cycle again, or be preserved for long periods; while some of the carbon will be stored in the seabed forever. According to the Blue Carbon report by UN, about global biological carbon or green carbon capture is accomplished by marine organisms. These marine organisms include phytoplankton, bacteria, seaweeds, salt marshes and mangroves. Marine plants or flora have high capacity and efficiency for carbon sequestration. The findings on marine biological carbon sink by worldwide studies are reviewed in this paper. Major mechanisms governing the marine biological carbon sink are described, along with its present status and approaches for its restoration. Additionally, the function of seaweed and bivalves mariculture as components of fisheries carbon sink is evaluated.