Abstract: 【Objective】 The effects of different irrigation amounts on the photosynthetic characteristics of Cabernet Sauvignon grapes were compared and analyzed under the soil conditions of the clay loam soil in northern Xinjiang in order to screen out the irrigation amount suitable for its growth, which will provide the scientific basis for cultivation application for the grape production in the future. 【Method】Taking the 3-year-old 'Cabernet Pearl' grape as the research object, three irrigation amounts were set: 220 m³/667 m², 260 m³/667 m², 280 m³/667 m², and the conventional irrigation amount 330 m³/667 m² was treated as a control, the net photosynthetic rate, transpiration rate and water use efficiency of each treated grape leaf were determined by portable photosynthetic system in the grape fruit expansion period. 【Result】Different irrigation amounts had different effects on the photosynthetic characteristics of Cabernet Sauvignon grapes. The daily average net photosynthetic rate of grape leaves was 13.11 μmol/(m²·s), which was 1.47% higher than the control, and the lowest daily transpiration rate was 4.48 mmol/(m²·s), 8.5% lower than the control; the daily mean value of water use efficiency was 3.07 mol/mmol, which was 8.8% higher than the control. 【Conclusion】 In the northern Xinjiang producing area, the water use efficiency of Cabernet Sauvignon grapes under 220 m³/667 m² was significantly higher than that of other irrigation treatments, and the water was used efficiently, which was more conducive to vegetative growth and balance of reproductive growth of vines.