To predict the influences of environmental change on the composition of communities, it is indispensable to also understand the regional drivers underlying the structuring of these communities. The goal of this study was to investigate the natural vegetation in the Lhasa River Basin of Qinghai-Tibet Plateau, and TWINSPAN and Canonical Correspondence Analysis (CCA) were used to explore the relationship between the community composition and the dominant environmental factors. The TWINSPAN quantitative classification divides the vegetation surveyed into 12 formation types. The 12 formation types include several vegetation types, including alpine shrub meadows, alpine shrubs, sparse grassland, alpine meadows, and alpine grasslands. The environmental factors explained a total of 20.4% of the community distribution variation, in which the average annual temperature of climatic factors, the altitude, and the latitude of spatial factors had a larger interpretation rate for the community distribution variation than did the topographic factors, such as slope and slope position. However,the average annual rainfall had no prominent impact on the change in community composition. The comprehensive analysis of spatial variation in the vegetation community could help us to understand the relationships between community formation and environmental factors.