The impact of global climate change on ecosystem function determines the status of population and community succession, and since arid areas are unique, they have become a hot spot for studying biological responses to environmental change. We used a sample plot method investigation to explore the response of plant niche to the soil water and salt gradient of the Ebinur Lake Basin. Based on a study of moisture, salt content, and plant niche characteristics for arid desert areas, the changes in community composition and niche responses to soil water and salt at different gradients were analyzed. The results showed the species composition of communities had a reverse "V" pattern along the water and salt environmental factor gradient (from high to low); these phenomena indicate that the interaction of water and salt concentration was the main reason the distribution of vegetation types was restricted. The niche breadth of Populus euphratica, Reaumuria soongorica, and Haloxylon ammodendron were larger than those of Tamarix ramosissima, Alhagi sparsifolia, and Glycyrrhiza uralensis at high saltwater soil environments. The niche breadth of Nitraria schoberi and Reaumuria soongorica were larger than those of Halimodendron halodendron, Glycyrrhiza uralensis, and Halocnemum strobilaceum at moderate saltwater soil environments. The niche breadth of Haloxylon ammodendron, Karelinia capsica, and Reaumuria soongorica were larger than those of Halocnemum strobilaceum at low saltwater soil environments. These phenomena indicate that the ecological niche of a population was not only determined by soil moisture and salinity, but also the ecological characteristics of the species in the desert area. At the species level, the niche overlap of the populations with large niche breadth between other species was generally large, but the niche overlap with smaller niche breadth species was not necessarily small; however, at the community level, there was a positive correlation between niche breadth and niche overlap. These phenomena indicate that a similarity in resource latitudes increased the niche overlap between the low niche breadth species, and the relationship between them was redundant when there was a transformation of niche breadth and niche overlap from the species to the community scale. The soil water and salt gradient showed a nonlinear correlation with community ecological amplitude. The distribution pattern of high water and salt in the soil had a certain promoting effect on the niche breadth of the community, while the distribution pattern of low water and low salt had a limited effect on niche breadth. The synergistic effect of soil water and salt determined the status of species in the community and determined the direction of community succession to the positive and negative poles.