Abstract: Arbuscular mycorrhizal fungi (AMF) play a vital role in maintaining the functionality and stability of plateau wetland ecosystems. However, the diversity of AMF communities along elevational gradients and their response to construction processes in the South-Tibet River Basin remain unclear. In this study, we conducted a wetland plant community survey, measured the physicochemical properties of water in situ, and collected sediment samples for further analysis across a high elevational gradient (4 200 to 5 100 m) in the South-Tibet River Basin. Results revealed that Glomus was the dominant genus within the Qinghai-Tibet Plateau wetland ecosystem. However, its relative abundance varied greatly with elevation, showing a significant declining trend with increasing elevation. Differences in AMF community composition were primarily due to species replacement. Variance partitioning analysis showed that the contribution of environmental variables to the AMF diversity-elevation patterns mainly involved sediment and water factors, with a lesser contribution from plant factors. These findings suggest that the establishment of the AMF community in the wetland habitat of the South-Tibet River Basin is predominantly governed by deterministic processes at high elevational gradients, reflecting a unique model of AMF community construction in the Qinghai-Tibet Plateau. However, further validation of these results is warranted.