Abstract: In order to determine the optimal irrigation mode of oil sunflower in Hexi Corridor, a field experiment was conducted in Wuwei Key Irrigation Experimental Station to research the effects of different irrigation amounts on dry matter accumulation and yield of oil sunflower.The results showed that less irrigation water would make the accumulation of dry matter stabilize early, and the accumulation value was low.The more irrigation water would make the accumulation of dry matter enters the rapid the rapidly rising stage later, resulting in a short duration of the rapid accumulation period, and the more dry matter accumulated mainly in stems and leaves.Timely irrigation at the flowering stage was conducive to dry matter accumulation.There was a parabolic relationship between water consumption and yield of oil sunflower during the whole growth period.According to the comprehensive analysis, the optimal irrigation mode was 4 times in the whole growth period (600m³/hm² at sowing stage, 400m³/hm² at the seedling stage, 400m³/hm² at budding stage, 400m³/hm² at the flowering stage and 1800m³/hm² of total irrigation water.Under these conditions, the yield of oil sunflower was 3725.09 kg/hm², and the water use efficiency was 1.49 kg/m³, which achieved the purpose of high yield and water saving.