[Objective] Taking Ordos Larus relictus National Nature Reserve as the research object,the effect of soil moisture gradient change on the spatial heterogeneity of vegetation and soil in the reserve was studied, and the spatial variation trend was revealed, in order to provide scientific basis for the research and protection of plant diversity in the reserve. [Method] Using mechanical sampling method, three transects were set perpendicular to the shore of the lake in the reserve to the north and south sides respectively, and the spatial distribution characteristics of plant communities and their soil physical and chemical properties at different distances from the shore of the lake were analyzed.[Results] (1) With the increase of the distance from the lakeshore, the plant community changed from the halophyte community to the psammophyte community, and the plant diversity index increased first and then decreased, and the plant diversity was the highest at 100-150m.The bulk density, soil moisture content, electrical conductivity, soil total porosity of Achnatherum splendens and Artemisia ordosica communities gradually decreased with the increase of lakeshore distance.(2)With the increase of lakeshore distance, the soil moisture content and electrical conductivity of soil decreased and changed greatly in different soil layers. The water content decreased by 10.79%, 10.09% and 7.67% in 0-10cm, 10-20cm and 20-30cm, respectively. The conductivity decreased by 35.73μs/cm, 34.20μs/cm and 32.63μs/cm, respectively.(3)Correlation analysis showed that plant diversity was significantly correlated with soil moisture content, electrical conductivity, total potassium, and clay content. Among them, water content had the strongest correlation with Simpson and Shannon-Wiener indexes and the correlation coefficient was equal, and the correlation coefficient was ?0.65 (p<0.05). The main driving factors of plant diversity showed obvious spatial differentiation ,in the range of 0-50m from the lake shore, plant diversity is mainly affected by soil moisture content, soil organic matter and total potassium. At 50-100m, the conductivity is the dominant factor ; soil water content and electrical conductivity at 150-200m are the key environmental limiting factors that determine the distribution of plant diversity. [Conclusion] Under the influence of lake waters, the protected area showed significant soil moisture gradient changes, and vegetation types and soil physical and chemical properties showed significant spatial differentiation characteristics driven by soil moisture gradient.