With the development of molecular biology, the role of soil microorganisms has changed the scientific understanding of formation and sequestration of soil organic carbon (SOC). Microbial residue combined with soil minerals to form mineral-associated organic carbon (MAOC), which has improved our understanding of soil organic carbon sequestration. MAOC is a fraction of soil organic carbon dominated by soil microbial residue carbon. It is mainly composed of identifiable microbial residue with low molecular weight bound to the mineral surface. As MAOC contributes more than 50% to soil organic carbon pool of grassland and agricultural ecosystems and has a long turnover time (centennial-millennial scale), the study of MAOC formation process and stabilization mechanism has become the focus of soil carbon sink in the context of carbon neutrality. Recent studies clearly indicate that the formation and stability of MAOC are not only mainly related to microbial residue carbon, but also closely associated with soil minerals. Based on this, we focus on the cutting-edge scientific issue of microbial carbon pump regulating soil organic carbon and provide an overview of the scientific framework on soil microbial residue contribution to MAOC. The aim is to reveal the contribution of LMW-DC (low molecular weight dissolved carbon substrate) from different sources to MAOC formation, and to explore the mechanism of selective adsorption of LMW-DC by soil minerals. Meanwhile, the relevant factors affecting the contribution of MAOC to stabilizing carbon pools are also discussed. It also provides an outlook on the future development of this research field, with a view to exploring the differences in the regulation of soil microorganisms in different ecosystems, soil types and soil depths from the molecular level, so as to provide a theoretical reference for the research on soil organic carbon sequestration and a scientific evidence for enriching soil carbon source/sink functions.