Carbon in soil is an important component of the global carbon cycle，and the processes of carbon cycling play a crucial role in regulating climate，with microorganisms being the key driving force behind carbon cycling in soil. This article reviewed the roles and mechanisms of microorganisms in the input of organic carbon in soil，formation and stabilization of organic matter in soil，the processes of decomposing and mineralizing organic matter in soil，and the effects of soil properties，climate conditions，plant factors，and human activities on microorganisms mediated carbon cycling in soil，especially the progress and theoretical updates in related studies. Microorganisms in soil can indirectly promote the photosynthesis in plant and the input of carbon in soil through its symbiosis with plants，and can directly participate in the fixation and transformation of carbon in soil. Microbial residues and their secretions play a crucial role in the formation of mineral-associated organic matter and aggregates in soil，which is beneficial for the long-term stability of organic carbon in soil. The microorganisms mediated effect of priming has a regulatory effect on the decomposition of organic matter in soil，which can affect the emissions of greenhouse gases such as CO₂ and CH₄ from the soil. Studies on the mechanism of microorganisms mediated processes of stabilizing the organic carbon and storing carbon in soil in the future should be strengthened and focus on the complex relationship between the structure and function of microbial community and the carbon cycling in soil，as well as their response to global changes. It will provide new insights for China to achieve its major strategic goals of “carbon peak” and “carbon neutrality” through enhancing the potential of carbon sequestration or the function of carbon sink with microbial activity.