In arid and semi-arid mining regions, understanding soil moisture dynamics and plant water uptake patterns is essential to addressing water scarcity and promoting vegetation restoration. This study focused on the arid and semi-arid Shendong Mining Area in western China. Through systematic sampling of precipitation, soil water (0-500 cm), surface water, and groundwater, combined with cryogenic vacuum extraction and laser spectroscopy, we quantitatively delineated the hydrogen and oxygen isotopic compositions of diverse water sources. Using the polygon method and the MixSIAR model, we assessed the water-use strategies of five representative plant species (Artemisia scoparia, Salix psammophila, Caragana korshinskii, Medicago sativa, and Populus simonii) at a regional scale. The results revealed that the slope of the soil water line (4.27) was substantially lower than those of the local meteoric water line (6.30) and the global meteoric water line (8.0). Shallow soil water (0-40 cm) exhibited pronounced isotopic enrichment and negative deuterium excess, indicating that strong evaporative fractionation governed shallow soil hydrology. Compared with soil water, the delta 2H and delta 18O values of groundwater were relatively small. Plant water-use strategies exhibited distinct vertical stratification: M. sativa extracted up to 78.7 % of its water from the shallow soil layer (0-40 cm), while A. scoparia obtained over 80 % from the upper 0-100 cm. In contrast, S. psammophila and C. korshinskii relied on 80.5 % and 78.9 % of their water from the middle to deep soil layers (40-300 cm), respectively, whereas P. simonii sourced 59.9 % of its water from depths exceeding 100 cm. Isotopic evidence highlighted significant risks of interspecific competition for water. Our study proposed optimized vegetation allocation strategies based on water niche differentiation, provided theoretical guidance for sustainable water resource management and ecological restoration in arid environments.