Water scarcity represents a critical constraint on development in arid regions, and the efficient water utilization strategies of desert riparian forests are vital for mitigating the impacts of global climate change and ensuring sustainable water resources. Stable hydrogen and oxygen isotopes, as primary tools for identifying plant water sources, are hindered by persistent isotopic offsets between xylem water and source water, which considerably complicates our understanding of plant water-use strategies. Thus, based on isotopic data from plants, soil water, and groundwater, we analyzed the driving factors of delta 2H offsets in the xylem water of Populus euphratica in desert riparian forests and evaluated the correction effects of the -8.1 parts per thousand, soil water line (SWL), and potential water line (PWL) methods under both single and dual isotope data input modes in the arid region of northwestern China. We found that the delta 2H offsets were primarily influenced by temperature, net radiation, and humidity, with relatively little influence from soil moisture and groundwater depth. In addition, dual-isotope mode incorporating PWL correction demonstrated the highest predictive accuracy for the water utilization strategies of P. euphratica in arid inland river basins. These findings provide critical insights for improving isotope-based quantification of plant water sources, which are essential for reducing uncertainties in Soil-Plant-Atmosphere Continuum models that utilize water isotopes to trace hydrological fluxes.