| An experiment was conducted out in Wuwei of Gansu Province in 2008. Water balance method was adopted to study the water requirement and water requirement law of spring wheat，spring maize, oil sunflower, capsicum and wheat intercrop maize, so as to give suitable irrigation program according to the growth period and water requirement law of crops. The results showed that spring wheat s water requirement was 480. 5 mm in the whole growth period, and the key imigation period appeared in jointing and heading stages; Spring maize's water requirement was 569.0 mm, and the key irmigation period appeared in shooting，trumpet and flling stages; Oil suflowver s water requirement was 291.0 mm，and the key irrigation period appeared in squaring and blooming stages; Capsicum s water requirement was 395.8 mm，and the key irrigation period appeared in fruit setting and expanding stages; Intercropped wheat and maize s water requirement was 636.4 mm，and the key irrigation period appeared in jointing and booting stages of wheat. The suitable irrigation times of spring wheat，spring maize, oil sunflower，capsicum， intercropped wheat and maize were four, five, two, five and six times，respectively. |