Abstract: Under the sustained warm-wet trend in northwest China, the interplay between agricultural water resources and crop production remains complex and poorly understood. This study comprehensively evaluates future agricultural water resources and climatic production potential for wheat and maize under climate change. Using Coupled Model Intercomparison Project Phase 6 (CMIP6) multi-model ensembles under SSP2-4.5 and SSP5-8.5 scenarios, we applied Delta statistical downscaling and a gridded crop model to assess blue water demand (BWD), green water availability ratio (GWAr), and climatic potential productivity from 2019 to 2100. The results show that: 1) significant spatiotemporal differences exist in the responses of precipitation and evapotranspiration across emission scenarios. Under SSP5-8.5, total precipitation increases but becomes more variable, while potential evapotranspiration increases 5.7 times faster than precipitation during 2071–2100. 2) BWD for both wheat and maize increases substantially, with maize showing higher BWD but generally lower GWAr. Under SSP5-8.5, the most marked increase in BWD occurs in Northern Xinjiang, whereas wheat BWD in the Hexi Corridor and Qaidam Basin remains relatively stable, accompanied by comparatively high GWAr. 3) Total crop yield for wheat and maize shows an upward trend under both scenarios, though yield per unit area exhibits spatial heterogeneity. By analyzing differences in agricultural water use and climatic yield potential across scenarios, this study offers a scientific basis for formulating differentiated water resource management strategies to ensure water and food security in northwest China.