In the paper, carbon cycling processes and carbon fixed by organisms in China marginal seas are reviewed. fluxes between atmosphere and seawater, carbon biological pump process, carbon sink/release in particulates and carbon transfer in fishing/culture. China marginal sea is a sink area of CO₂ the air, but some coastal parts are source areas such as the Jiaozhou Bay and the Changjiang estuary. The mean annual sink strength of atmospheric CO₂ in China marginal seas is about 30 million ton carbon per year. The source/sink strength is controlled by sea surface temperature(SST), phytoplankton production and seawater mixing process in different sea-regions and seasons. China marginal seas, in which 65.3% carbon is fixed in spring and summer. The carbon fixation ability of the South China Sea is about 4.16×10⁸ t/a, which is double of that in Bohai Sea, the Yellow Sea and the East China Sea. F. In recent years, the yield of China marginal seas is about 1.20–1.50 ×10⁶ t/a, so their fixed carbon is about 4.0 ×10⁵ t/a. If the seaweed yield amount increase by 5% every year in China marginal seas, carbon fixed amount of the large-sized economic seaweeds may reach to 9.3 ×10⁵ t/a up to 2020. Therefore, algae breeding is an important technique for increasing marine carbon sink with multi-values. To reveal the fishing/culture eco-environment, establish the method for grading the carbon sink of fishing/culture and study the recycling period of fishing/culture carbon sink are very important in the future.