For the purpose of conserving soil and water as well as restore ecosystems, maintaining soil nutrient levels in dry-hot valley reservoir regions is essential. However, the spatial characteristics of soil nutrients within reservoir areas remain poorly understood. This study focused on the Wudongde and Baihetan reservoir areas located in the lower reaches of the Jinsha River. Surface soil samples were collected from the head, middle, and tail of the reservoir, including both surface layer (0-10 cm) and subsurface layer (10-20 cm), and the soil nutrient content were measured. Based on the second soil nutrient grading standard, a soil nutrient spatial differentiation analysis model was developed by integrating fuzzy comprehensive evaluation, the random forest model, and natural breakpoint analysis. This model aimed to elucidate the spatial differentiation characteristics of soil nutrients and propose zoning management strategies. The findings indicate that: (1) the soil in the study area was weakly alkaline, with high contents of soil organic matter, total potassium, available potassium, available manganese, and available copper, all of which were at level 1. Available zinc content was at level 2, while cation exchange capacity, available boron, and available molybdenum contents were low, at level 4, and total phosphorus was at level 5; (2) the nutrient in the 0-10 cm soil layer is generally high, ranging from 0.53 to 0.66; the highest values were found in the reservoir tail areas of Wudongde and Baihetan; for the 10-20 cm soil layer, the nutrient content generally ranges between 0.43 and 0.58, with the highest values located in the middle sections of the reservoirs; (3) Surface soil nutrient variation was mainly influenced by human activities and vegetation, whereas the subsurface soil was more affected by topography and soil properties. Most areas of the reservoir head were in the soil nutrient conservation zone, the reservoir middle was generally in the nutrient recovery zone, and the reservoir tail was in the risk prevention and control zone.