【Objective】 The Yarlung Zangbo River is the most important river on the Tibetan Plateau, and the study of aboveground biomass and species diversity of the Yarlung Zangbo River is of great significance to the understanding of grassland resources and ecological conservation in the region. 【Methods】 This study investigated the vegetation characteristics of alpine meadows in the upper reaches of the Yarlung Zangbo River according to the elevation gradient, and studied the distributional differences of aboveground biomass and species diversity at different elevation gradients, the relationship between aboveground biomass and species diversity, and the effects of related environmental factors on aboveground biomass and species diversity. 【Results】 (1) There was no significant relationship between elevation and aboveground biomass. (2) Elevation and diversity indices showed a significant negative correlation: the Shannon-Weiner index and Patrick index showed a decreasing trend with elevation. (3) Aboveground biomass and diversity showed a negative correlation, and the explanation of aboveground biomass by the Shannon-Weiner index reached 70% (P<0.01). (4) Species diversity showed a significant positive correlation with temperature and precipitation (P<0.05), species diversity showed a negative correlation with elevation (P<0.05), and aboveground biomass had no significant relationship with elevation, temperature and precipitation (P>0.05). 【Conclusion】 The results of this study can help to improve the basis for the rational utilization of grassland resources and species diversity conservation in the upper Yarlung Zangbo River basin.