Reaumuria songarica and Haloxylon ammodendron communities in the Karamaili Mountain Hoofed Wildlife Nature Reserve were taken as the study objects. Regular soil and plant surveys were conducted on fixed plots during the plant growth season to analyze the dynamic changes in soil clay content, moisture, and surface plant diversity in the 0-100 cm soil layer. The results showed that soil physicochemical properties and vegetation diversity of different plant communities were significantly different. Soil clay content and fractal dimension under Reaumuria songarica were higher than those under Haloxylon ammodendron in all soil layers. The maximum values of the two indicators were located in 40-60 cm soil layer under Reaumuria songarica (3.40% and 2.73, respectively), and located in 0-20 cm surface layer under Haloxylon ammodendron (2.22% and 2.69, respectively). The gravity centers of soil clay content and moisture under Reaumuria songarica were located in the shallower soil layer, with an average depth of 28.7 cm and 34.5 cm, respectively, which were 29.8 cm and 36.0 cm, respectively under Haloxylon ammodendron. Soil moisture under Reaumuria songarica was generally high, especially during the dry season, which is beneficial for the growth of shallow rooted plants in early spring, and the stability of the ecosystem due to its high water retaining capacity, indicating Reaumuria songarica has better vegetation conditions due to its superior soil structure and water retaining capacity, whose species diversity index and the numbers of families, genera, and species were higher than those of the Haloxylon ammodendron, with 20 species belonging to 17 genera in 12 families, and 13 species belonging to 10 genera in 8 families, respectively. Soil clay content and moisture had positive correlations with plant diversity, indicating that soil clay content and moisture are not only the key indicators for evaluating soil texture and moisture status, but also important references in evaluating plant diversity, which provide important references for ecological protection in the Karamaili Mountain area.