Abstract: Objective To reveal the differentiation pattern of slope gradient on the diversity of lemon mallow communities and soil properties in the Mu Us Sandy Land, to elucidate the vegetation-soil synergistic response mechanism, and to provide theoretical support for the restoration of sandy ecosystems. MethodsThree slopes were selected in Bletchintan National Nature Reserve of Ningxia, including pre-slope (P1), top of slope (P2), and post-slope (P3), and the indicators of vegetation community structure, soil physicochemistry and so on were determined, and one-way analysis of variance (ANOVA) and redundancy analysis of variance (RDA) were used to analyse the effects of the slope gradient. Results (1) Diversity: Slope position significantly regulated the diversity of the shrub layer (P<0.05): Shannon index (P2:0.6>P3:0.58>P1:0.45), Simpson index (P2:0.41>P3:0.4>P1:0.32); although there was no significant difference in the herb layer (P>0.05), all indices showed a P2>P3>P1 trend. Although there was no significant difference (P>0.05), all indices showed the trend of P2>P3>P1. (2) Soil properties: the vertical differentiation of soil properties was significant: the highest water content P2 was found in 0-20 cm (wind erosion was weak), and the highest water content P1 was found in 20-40 cm (moisture enrichment in deeper layer); ammonium nitrogen was enriched in the surface layer (P2>P1>P3), and nitrate nitrogen migrated vertically to the deeper layer (P1>P2>P3). (3) Correlation: RDA showed that soil organic matter (SOM) was significantly and positively correlated with Shannon's diversity (r=0.82*) and nitrate nitrogen (AN) with Simpson's dominance degree (r=0.75*) (Axis 1 explanation rate 98.13%).ConclusionSlope position shapes lemon community pattern through water redistribution and nutrient heterogeneity, deep soil moisture and nitrate nitrogen are the key factors driving the community construction, and the top of the slope combines high diversity and deep moisture advantage, which is a priority area for ecological restoration as it attenuates wind erosion and optimises water redistribution through topographic shelter.