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Abstract. Improvements in grain yield of winter wheat in arid and semi-arid areas need research focused on reasonable water application control on plant-soil interface. Four different irrigation depths decided by root distribution (surface, 60% of the depth that root distribution, 75% and 90%, namely D0, D60, D75 and D90) at different growth stages were conducted in a field experiment using PVC growth tubes to investigate the physiological responses. Leaf area index (LAI), chlorophyll content (Chl), photosynthesis rate (Pn), transpiration rate (Tr), stomatal conductance (Gs) and the ratio of intercellular CO₂ and atmospheric CO₂ (Ci/Ca) were increased under deep irrigation depths than surface treatment, and the value of those in D75 were greater, compared with D60 and D90. The highest grain yield was obtained in D75 with a higher root dry matter and water use efficiency (WUE). The conclusions of this study indicate that the optimum irrigation depth based on measuring the 75% of root distribution (D75) increased the photosynthesis capacity, dry matter weight, yield and WUE of winter wheat, which can help in understanding the mechanism of controlling water distribution with depths, and enhancing the water-saving irrigation management of winter wheat.