In the past decade, a series of progresses have been achieved in interaction between marine sedimentary organic matter and clay minerals. Research advances are summarized in the preservation of marine sediment organic matter by clay minerals adsorption, and its significance in global carbon cycle is discussed thereafter. Adsorption of organic matter to clay minerals occurs everywhere in nature. Organic matter can be adsorbed not only by small intercrystalline mesopores with van der waals force and chemical bonds, but also by interlayer spaces with surface bondage. Adsorption ability of clay minerals is related to types and structures, component and characteristic of organic matter, as well as physicochemistry condition of agential . It was suggested that clay minerals play an important role in protecting marine sedimentary organic matter by adsorption. Sedimentary and buried organic matter can be effectively protected from enzymes by decreasing mesopores of clay minerals after absorption of organic matter. Being a tie between activity carbon reservoir and permanent carbon reservoir, clay minerals in marine sediments translate carbon of atmosphere and ocean reservoir with rapid cycle into lithosphere reservoir via adsorbing organic matter, leading to missing carbon sink. Thus, clay minerals control function of carbon source and sink of oceans and have great influence on global carbon cycle and climate change.