[Objective] The species composition and diversity characteristics of different types of vegetation communities in the Zhangye desert-oasis transition zone in Gansu were analyzed and studied, as well as the correlation between plant community characteristics and soil moisture content,, it provides a scientific basis for the evaluation of water and soil conservation benefits in the region. [Methods] Choose different types of desert vegetation, investigate and determine the diversity of different types of vegetation community plants and 0 to 120 cm of soil moisture content. [Results] The results showed that:①There are 6 vegetation types in this area, the vegetation structure is very simple, and the species composition is dominated by drought-tolerant and super-drought-tolerant small shrubs, semi-shrubs and herbs such as Reaumuria songarica, Sympegma regelii, Caroxylon passerinum, Aristida adscensionis, Grubovia dasyphylla that suitable for arid desert habitats, and the plant community is a type of shrub and grass community, with a relatively small species diversity index. ② The change of soil moisture in the vertical direction presents a "double peak", and the soil humidity gradually increases from the surface layer to the deep, it rises to the "first peak" at 20-40 cm, drops to a lower level at 40-60 cm, and gradually rises at 60-120 cm, until to the "second peak" at 120 cm.③ The vegetation height, vegetation density and vegetation cover of each plant community increased with the increase of soil moisture content. The vegetation height was significantly positively correlated with the soil moisture in the soil layer of 40-120 cm, and the density and vegetation cover of herbaceous plants and shrubs were significantly positively correlated with the soil moisture content in the layer where their root systems were mainly distributed. [Conclusion] In the desert oasis transition zone where the moisture content of the surface soil (0-20 cm) deep soil (40-80 cm) is less than 2 per cent, it is appropriate to plant arid shrubs such as Reaumuria songarica, Sympegma regelii, Nitraria tangutorum and other herbaceous plants such as Aristida adscensionis, Salsola tragus, Grubovia dasyphylla, Eragrostis pilosa and Artemisia scoparia, etc.; and in the desert zones where the moisture content of the surface soil and the deep soil is more than 2 per cent, it is appropriate to plant arid shrubs such as Reaumuria songarica, Caroxylon passerinum, etc., and herbaceous plants such as Artemisia frigida, Artemisia xerophytica and Carex duriuscula, etc., which are capable of effectively promoting ecological recovery and reconstruction.