Abstract: Abstract：Water temperature is an important factor affecting the effect of crop irrigation. In order to clarify the effect of low-temperature water at the intake of a specific reservoir on irrigation and the effect of various low-temperature water mitigation measures in the irrigation area, taking the first phase of the North Main Canal of Xiangjiaba Irrigation Area as the research object, quantitatively analyze the effect of low-temperature water mitigation measures in the irrigation area. The results show that compared with the natural water temperature of the dam site, the maximum decrease of water temperature in irrigation area can reach 2.1℃ during the operation of single reservoir (in the near future), and it can reach 3.1℃ after combined operation of cascade power stations (in the long term). The long-term low-temperature water effect of the dam construction is greater than that of the near future. The irrigation water temperature of nearest ditch (Baixi Ditch) decreases by 3.1℃ in April, while that of the far ditch (Liangmu Ditch) decreases by 1.3℃.The farther the irrigation canal is from the intake, the smaller the decrease of irrigation water temperature, the effect of low-temperature water in front of 38 km of the main canal in the north of Xiangjiaba is significant, while less effects beyond 38 km. The temperature increase effect of stoplog gate is similar to that of sunning water pool, the temperature increase effect is about 0.4 ~0.9℃ in April. Using existing water conservancy facilities such as ponds, pits to supplement the sunning water pools to increase the temperature of low-temperature water has a significant improvement effect, the range of temperature increase in April is about 1.3-1.7℃. The research results can provide decision-making basis for the management departments of lake and reservoir to make short-term and long-term operation plans.