Abstract: Under agricultural intensification, excessive inputs of water and nitrogen fertilizers have led to severe over-extraction of groundwater in the Piedmont Plain of the Taihang Mountains, resulting in a decline in the environmental carrying capacity of soil and other resources. Identifying the primary limiting factors of water and nitrogen in this region and optimizing the application of nitrogen fertilizers and irrigation are critical for improving crop yield, quality and enhancing resource use efficiency in arid areas. This study focused on the widely cultivated high-quality strong-gluten winter wheat variety ‘Gaoyou 2018’ in the Piedmont Plain of the Taihang Mountains. Four water treatments (W0, W1, W2, and W3, with an increment of 75 mm of water at the jointing, heading, and filling stages) and three nitrogen treatments N250: conventional farming practice, 250 kg(N)·hm^–2; N200: 20% reduction; N150: 40% reduction) were established to investigate the effects of water saving and nitrogen reduction on nitrogen translocation, water and nitrogen use efficiency, and grain quality in winter wheat. Compared to conventional irrigation, water-saving treatments significantly reduced yield by 16.9%–60.7%, primarily due to decreases in grain number per spike and thousand grain weight. Compared with N250, nitrogen reduction treatments N150 significantly increased the average aboveground biomass (2.5%–21.6%) across different water-saving treatments. Water-saving treatments W0 enhanced the contribution rate of nitrogen transfer amount to grain nitrogen (43.9%–131.8%), ultimately increasing curde protein content in grain (10.9%–36.3%), but significantly reducing total protein content (7.6%–46.5%). Greater reductions in irrigation led to higher crude protein content, but lower total protein content. Under W0, total protein content was significantly higher in N150 and N200 than in N250 by 37.5% and 24.7%, respectively. Compared to W3, water-saving treatments significantly reduced nitrogen use efficiency (18.8%–61.0%) and nitrogen partial factor productivity (16.7%–60.3%), but significantly increased yield (3.1%–38.2%) and water productivity at the biomass level (41.85%–93.4%). The yield was significantly positively correlated with nitrogen use efficiency, total protein content, thousand grain weight, and nitrogen partial factor productivity. The contribution rate of nitrogen transfer to grain nitrogen was significantly positively correlated with grain protein content, water use efficiency at the yield level, and water use efficiency at the biomass level. Comprehensive analysis revealed that the W3N150 treatment scored the highest (2.94), with significant differences among irrigation treatments but no significant differences among nitrogen treatments. Therefore, water-saving treatments can be considered as the primary limiting factor in this region, whereas nitrogen reduction treatments serve as a key strategy for reducing inputs and provide important guidance for dual-reduction strategies in the area.