干旱区农业用水最显著的特点是季节性强，无灌溉即无农业。合理利用干旱区有限的水资源，保证农业可持续发展，是农业高效用水中有待解决的课题之一。以内蒙古河套灌区解放闸灌域为代表性地区，结合其自然条件，建立了该地区灌溉用水中长期预报模型。所建模型对于合理利用干旱区有限水资源，提高引水效益，保证农业可持续发展，是一种重要的措施。 The most notable feature of agricultural water in arid zones is seasonal and no agriculture without irrigation. Rational use of arid area of ​​limited water resources to ensure the sustainable development of agriculture is one of the outstanding issues in agricultural water use. Taking the Jiefangzha irrigation area of ​​Hetao Irrigation District in Inner Mongolia as a representative area, combining with its natural conditions, a medium- and long-term forecasting model of irrigation water in this area was established. The model is an important measure to make rational use of the limited water resources in arid area, increase water diversion benefit and ensure the sustainable development of agriculture.