[Objective] The appropriate quantities of water and fertilizer were determined to understand their efficient utilization for walnut trees under drip irrigation in the Northwest Margin of Tarim Basin, which is a main production area of walnuts. The aim was to provide guidance for the extent of irrigation and nitrogen input to be used for drip irrigation for local dense planting of walnut trees.[Methods] The field experiment was conducted in the fruit trees experimental base of Xinjiang Agricultural University. Taking the nine-year-old dense planting of walnut trees (variety "Xinwen 185") as the research object, three irrigation levels (W₁:375 mm, W₂:435 mm, W₃:495 mm) and three fertilizer doses (F₁:2 250 kg/hm², F₂:4 500 kg/hm², F₃:9 000 kg/hm²) were arranged to study the effects of water-fertilizer coupling on walnut yield, walnut quality, and water and fertilizer utilization efficiency under drip irrigation. Mathematical models of the relationship between water-fertilizer investment and walnut indicators were established through multiple quadratic regression analysis.[Results] The effects of irrigation and fertilizer on the soil NO^-₃-N in the walnut tree growth periods of hard stone and oil conversion, on the walnut yield, quality, irrigation water use efficiency (IWUE), and partial factor productivity (PFP) reached significant levels (p<0.05). The interaction effects of irrigation and fertilizer on walnut yield, IWUE, and PFP reached significant levels (p<0.05). Hard stone and oil conversion periods were the key periods of fertilizer demand for walnut trees. The F₃ treatment resulted in the accumulation of soil nitrate nitrogen. There was no significant difference in the effects of W₂ and W₃ treatments on the quality, yield, and PFP of drip irrigation of walnut trees, which were significantly different from those of W₁. The effects of fertilizer application on the kernel yield, yield, IWUE, and PFP of walnut trees were significant.[Conclusion] Around Tarim Basin, the suitable ranges of water and fertilizer applications for the whole growth period of walnut trees were, 438 to 469 mm (including winter and spring irrigation) and 7 074 to 7 168 kg/hm², respectively, including 3 144 to 3 186 kg/hm² urea and 3 930 to 3 982 kg/hm² monoammonium phosphate.