Abstract: Arbuscular mycorrhizal fungi (AMF) play an important role in promoting the function and stability of plateau wetland ecosystems. However, their community diversity across elevation gradients and their construction process in the South-Tibet River Basin remain unclear. We found that the composition of AMF community varied greatly with altitude through cross-elevation sampling in the wetlands of the South-Tibet River Basin. The variation analysis showed that the contribution of AMF community was mainly composed of sediment and water, while the contribution of plants was relatively low. In all sampling sites, the AMF community composition was dominated by species replacement process. In the whole elevation gradient, AMF community assembly was mainly dominated by heterogeneous selection during deterministic process, indicating that AMF community assembly was mainly influenced by abiotic factors in the wetland environment of the South-Tibet River Basin.