Abstract: Due to the supply of deep matters, hydrothermal system provides abundant nutrients to the ocean, which supports the growth of a large number of hydrothermal organisms, making the hydrothermal system a hotspot for organic carbon production. The hydrothermal system is also an important source of mercury in the ocean, and has a large proportion in the global ocean mercury flux. Mercury and organic carbon have strong bonding ability, and the combined mercury deposit to sediments of hydrothermal system with organic carbon, which records the changes of hydrothermal and volcanic environment, and also provides an explanation for the changes of organic carbon in volcanic and hydrothermal activities. Due to the important role of hydrothermal systems in organic carbon production, the study of hydrothermal helps to unravel the complex organic carbon cycle and understand the importance of hydrothermal systems in the organic carbon cycle. Besides, the study of the coupling of mercury and organic carbon in volcanic and hydrothermal activities is an important means to unravel the changes of organic carbon burial driven by volcanic activities in geological times. In this paper, the production, burial and transformation process of organic carbon in hydrothermal system were reviewed, and the coupling research of organic carbon and mercury in hydrothermal system was summarized. It is concluded that volcanic and hydrothermal events in geological history have been recorded by mercury, indicating the important influence of volcanic activity on organic carbon production over a long time scale. Based on the great record of mercury in sediments for hydrothermal and volcanic activities, the influence of hydrothermal and volcanic activities on the organic carbon cycle has been studied more precisely. By summarizing the previous studies on the organic carbon cycle of hydrothermal systems and the coupling of mercury and organic carbon on geological time scales, this paper further looks forward to the research on the coupling of mercury and organic carbon in submarine hydrothermal events and activities, with the aim of further improving the organic carbon cycle process in this complex region of hydrothermal and providing a theoretical basis for further research on the global organic carbon cycle.