Abstract: Biological soil crust is an organic complex formed by the cementation of soil microorganisms and spore plants such as algae,lichens,and mosses with surface soil particles,occupying an important position in degraded or damaged ecosystems.Biological soil crust can not only improve soil structure,enhance soil stability,but also improve soil nutrient content and enzyme activity.In the past,research on biological crusts mainly focused on their function and effects in desert and arid and semi-arid region.As an important surface cover in terrestrial ecosystem,biological crusts can also affect the content and stability of soil organic carbon,readily oxidizable carbon through photosynthesis.In recent years,how biological soil crusts affect the global carbon cycle and carbon balance has gradually become the mainstream direction of researchers.This study summarized the changes of soil physical and chemical properties,soil carbon cycle and soil respiration under biological crust mulching,summarized the research work and achievements of biological soil crust affecting the ecosystem carbon cycle,and looked forward to the future research focus,so as to provide new reference for achieving the goal of ‘carbon neutrality’.