The paper analyzes the soil water dynamics and water requirement law of alfalfa,feed maize and ensile maize under 3 kinds of water-saving irrigation conditions through experimental study on the crops. 对节水灌溉条件下的紫花苜蓿、饲料玉米和青贮玉米需水量进行了试验研究,分析了不同灌溉水平下3种饲草料作物的土壤水动态和需水规律。