Understanding how organisms adapt to drought conditions is of great importance for future ecological conservation and restoration efforts, as climate models predict planet-wide increases in the frequency of drought events. Soil nematodes play an important role in various key ecological processes and functions. However, how nematode communities respond to drought in savanna ecosystems remains largely unexplored. Here, we characterized soil nematode communities and soil properties across two seasons in plots located at four different elevations in the Yuanjiang savanna, China. We explored distributions of nematode abundance and diversity and used a null model to identify the mechanisms underlying nematode community assembly. We found that soil moisture was the primary driver of nematode abundance, with higher soil moisture directly promoting omnivore-predators diversity and shaping patterns of diversity in other nematode groups via niche divergence. Meanwhile, ammonium nitrogen influenced the diversity and abundance of plant parasite. Total phosphorus influenced bacterivore and plant parasite diversity. Furthermore, soil moisture determined the composition of soil nematode communities, and the stronger the determinism in community assembly, the closer the relationship between soil moisture and community composition and abundance. Seasonal variation in precipitation and microbial biomass carbon regulated the determinism of community assembly. Overall, our findings highlight the pivotal role of soil moisture in shaping patterns of nematode abundance and reveal the key factors influencing soil nematode community assembly in dry-hot regions.