Abstract: The crop water requirement is one of the most important factors in farmland water circulation system. study the effects of climate warming on water requirement of major crops in irrigated oasis in Hexi corridor when 1-4℃ temperature rise in the future scenarios. The results show that climate change will have great impact on water requirement of cotton and corn, followed by spring wheat. when the temperature rises 1-4℃ during the growth period, cotton, water requirement of cotton will increase by 2.17%-12.66%, equivalent to 15.00-83.00 mm; corn will increase by 1.90%-11.49%, equivalent to 14.60-82.50 mm; wheat will be increase by 1.80%-10.03%, equivalent to 9.70-50.70 mm.There are certain regional differences which the impact of climate change on crop water requirements. When the temperature increases 1℃, the crop water requirement of Wuwei in arid regions slightly larger than Dunhuang in extreme arid region; When increases 2℃, the demand almost equivalent. Dunhuang is greater than the Wuwei if increased 3 and 4℃. According to the current planting planning in Hexi Oasis, the given temperature scenario will cause an additional water requirement of 0.11,0.21,0.37,0.62 million m³ for cotton, 0.16,0.33,0.56, 0.93 million m³ for corn; and 0.14,0.26,0.45,0.71 million m³ for spring wheat. The total irrigation water increase 0.41,0.80,1.38,2.25 billion m³. Climate warming will make the situation of water shortage more severe.