[Objective] To investigate the effects of different vegetation configurations on understory plant diversity and soil nutrients in sea buckthorn forests, addressing ecological degradation in open-pit coal mine waste dumps, and to identify suitable ecological restoration configurations[Methods] The study area was the Manlailiang open-pit coal mine waste dump in Yijinhuoluo Banner, Inner Mongolia. Vegetation surveys and soil chemical property measurements were conducted across three sea buckthorn configuration types: pure sea buckthorn forest (Type I), alfalfa co-planted with sea buckthorn in the same year (Type II), and alfalfa planted two years prior to sea buckthorn (Type III). alfalfa and sea buckthorn co-planted in the same year (Type II), and alfalfa planted two years prior to sea buckthorn (Type III). Vegetation community surveys and soil chemical property measurements were conducted. Ecological effects were comprehensively evaluated using Pearson correlation analysis and principal component analysis (PCA). [Results] (1) Significant differences (p<0.05) were observed in understory vegetation diversity and soil nutrient content among the three configurations, with species diversity indices following the order: Type I > Type III > Type II. (2) In the 0–40 cm soil profile: while total nitrogen, total phosphorus, total potassium, available phosphorus, and available potassium all showed: Type III > Type I > Type II. (3) Correlation analysis revealed that in the 0–20 cm soil layer, all soil indicators except alkali-hydrolyzable nitrogen showed positive correlations with the species diversity index; In the 20–40 cm soil layer, total potassium and available potassium positively correlated with the species diversity index, while other soil indicators negatively correlated with it, with alkali-hydrolyzable nitrogen showing a significant correlation. (4) In principal component analysis, Type III scored highest on the first principal component, while Type I scored highest on the second principal component and the composite score. [Conclusion] Significant differences exist in soil chemical properties and biomass among different vegetation configurations of sea buckthorn forests. Pure sea buckthorn stands demonstrated the best overall performance in promoting community species diversity and enhancing soil nutrients, while the alfalfa-sea buckthorn co-planting model performed the worst. These findings provide scientific basis for ecological restoration of mine waste dumps.