[Objective] The hydrogen and oxygen isotope characteristics of plant water under different water gradients were analyzed and compared in order to provide a theoretical basis for the selection of suitable species for ecological protection, erosion control, and sand control in the Yellow River basin.[Methods] Using hydrogen and oxygen stable isotope technology, based on the HYSPLI4 air mass trajectory model and the Bayesian mixed model MixSIAR, the potential water utilization efficiency of dominant plants under different water gradients along the banks of a major tributary of the Yellow River, was analyzed, and water utilization strategies of different plants were then proposed.[Results] The atmospheric vapor was mainly affected by the local evaporation air mass and northwest monsoonal transport during the sampling period. Shallow soil water (0-30 cm) was the main water source for plants in the floodplain. On terraces of the river valley, herbaceous plants mainly used shallow and middle soil water (0-70 cm), while shrubs and tall herbs used water from deeper soil layers (70-100 cm). The phenomenon of ecohydrologic niche separation between plants was apparent.[Conclusion] When water is scarce, shrubs are more competitive because of their water use patterns. Shrubs are suitable species for ecological protection, erosion control, and sand control in the Yellow River basin.