Abstract: In order to research the efficient water-saving irrigation system of ensile maize in Xilin River Basin, different irrigation experiments have been carried out for two consecutive years, and the irrigation system of ensile maize under drip irrigation was studied. The results showed that, the soil water consumption rate was the lowest from the jointing stage to the tasseling stage; crop coefficient, yield response coefficient and evapotranspiration were the highest from the shooting phase to tasseling stage, which was the critical period of water requirement of ensile maize. Based on the field experiment, WIN ISAREG was used to appraise the actual irrigation system, simulated a variety of combination plans, and the optimization irrigation system was obtained. Ensile maize field was irrigated eight times during the plant growth period, and the irrigation quantity was 200 mm, the rate of yield decline was 5.6% , and irrigation efficiency reached 100% . The results can provide a reference for effective utilization of water resources and irrigation forecast in Xilin River Basin.