Abstract: In order to determine the silage maize in different stages during the growth period of water demand and water requirement, put forward reasonable irrigation system of corn silage. This paper got the silage corn water requirement and water requirement law preliminary by analyzing the 2010 Aletai region silage corn irrigation experiment data. The results showed that, silage corn water requirement was 593 mm under the suitable soil moisture conditions, water requirement law was early and late take less water, fertility period needs much more water, which was parabola. Water consumption intensity was changing with temperature obviously. Water consumption coefficient of seedling stage was minimum value in all stages, but maximum value appeared at booting-blossom period except booting-blossom period drought treatment appeared at tillering and jointing stage. Yield maximum was 54.5 t/hm2 under full irrigation, and the minimum was 22.9 t/hm2 of the elongation stage and booting-blossom period drought. Booting-blossom period under light drought treatment got maximum moisture productivity, which was 12.42 kg/m3. In the case of sufficient water, irrigation amount of silage corn irrigation amount wasn’t exceeding YM8; but when the irrigation water was very scarce, in order to ensure that the limited water resources were fully utilized, should use the YM3 mode.