[Objective] The species composition and diversity characteristics of different types of vegetation communities along with the correlation between plant community characteristics and soil moisture content in the Zhangye desert-oasis transition zone in Gansu Province were analysed, in order to provide a scientific basis for the evaluation of water and soil conservation benefits in the region. [Methods] Different types of desert vegetation were chosen, and the diversity of different types of vegetation community plants and soil moisture content at 0—120 cm were investigated and determined. [Results] ① There were six vegetation types in this area, and the vegetation structure was very simple, and the species composition was dominated by drought-tolerant and super-drought-tolerant small shrubs, semi-shrubs and herbs such as Reaumuria songarica, Sympegma regelii, Salsola passerina, Aristida adscensionis, and Bassia dasyphylla that were suitable for arid desert habitats. The plant community was a shrub and grass community with a relatively small species diversity index. ② The change of soil moisture in the vertical direction presented a “double peak”, and the soil humidity gradually increased from the surface layer to the deeper layers; it increased to the “first peak” at 20—40 cm, decreased to a lower level at 40—60 cm, and gradually increased at 60—120 cm, until to the “second peak” at 120 cm. ③ The vegetation height, density, and cover of each plant community increased with increasing soil moisture content. Vegetation height was significantly positively correlated with 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 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) and deep soil (40—80 cm) was less than 2%, it is appropriate to plant arid shrubs such as R. songarica, S. regelii, Nitraria tangutorum and other herbaceous plants such as A. adscensionis, Salsola tragus, B. dasyphylla, Eragrostis pilosa and Artemisia scoparia. In the desert zones where the moisture content of the surface soil and the deep soil is more than 2%, it is appropriate to plant arid shrubs such as R. songarica and S. passerina and herbaceous plants such as Artemisia frigida, Artemisia xerophytica, and Carex duriuscula, which are capable of effectively promoting ecological recovery and reconstruction.