Abstract: Forest ecosystem is the largest organic carbon sink on the earth,playing a significant role in maintaining global C-cycling and mitigating greenhouse gas emission. Regulating soil carbon sequestration and reducing carbon loss are critical strategies to increase the carbon sink and realize “carbon neutral” target. So far,the prevailing view of soil organic carbon formation has shifted from recalcitrant plant residue carbon to microbial-derived residue carbon accumulation theory. However,the in-depth understanding of this theory is still lacking. Tannins are a group of plant secondary metabolites,playing important roles in plant-litter-soil interactions. This study aims to explore the role of tannin in promoting soil organic carbon stabilization and further increase soil carbon sink via multiple mechanisms(i. e. binding microbial necromass,inhibiting soil enzyme activity and enhancing mineral protection). These results may help to provide theoretical basis for optimize land management and increase soil carbon sequestration.