Abstract: Arbuscular mycorrhizal (AM) fungi are one of the most important soil microorganisms in terrestrial ecosystems. Through hyphal fusion, the mycelium of AM fungi could form arbuscular mycorrhizal network (AMN) widely in the underground habitats. It has been demonstrated that AMN plays important roles in ecosystems. AMN could change the soil physical and chemical properties directly and change the microenvironment for soil microorganisms. Thus, AMN could influence the soil microbial community structure. AM fungi also could absorb nutrients through the external hyphae from soil. Then the nutrition could transport to different host plants through the mycelium with AMN, which could affect the dynamics of plant community structure. In order to discover the role of AMN in ecosystem, we reviewed the function of AMN in ecosystem, including: 1) the formation strategy of AMN through the external hyphae of AM fungi fusion in the soil; 2) the regulation of AMN on soil microorganism community structure and  ecological function; 3) the mechanism of AMN to adjust the soil  resources distribution, and their influence on intra and interspecific plant competition, as well as the host plant species diversity and abundance in ecosystem; 4) the relationship between AMN and global changes in the atmospheric nitrogen deposition, atmospheric CO₂ and temperature, and the role of AMN in the stability of ecosystem. The future development directions and application prospects were also discussed.