In arid areas, the vegetation is sparse, the ecological environment is fragile, the number of vegetation species is scarce, the community structure is unstable, and the impact of different environmental factors on the plant community is unclear. In this study, the lower reaches of the Tarim River were used as the study area, and the plant community characteristics and environmental factors were investigated. TWINSPAN and CCA were used to undertake a multivariate statistical analysis of vegetation in the region. The objectives of this study were to identify: 1) the optimal vegetation structure for controlling desertification and 2) the key factors affecting vegetation characteristics and the relationship between plants and these key factors. The results showed that the tree-shrub-grass community structure is the most stable and provided the best windbreaks and sand fixing abilities. In addition, attention should be paid to the restoration and reconstruction of herbage when constructing shelter forest. The main environmental factors determining the distribution of plant community types are groundwater depth and soil water content in the lower reaches of the Tarim.