A test of three types of irrigation was carried out in the oasis area of the arid region in Minqin County for the study of the effects of the controllable altatively root-partitioned irrigation (CARI) on c ( Zea mays L. ) growth, root distribution, and the water-saving benefits. The research results showed that the altatively interspaced furrow irrigation (AIFI) could significantly increase the water use efficiency of irrigation. The water use efficiency of the FI was 2.6 - 2.7kg/m3 and that of the AIFI reached more than 4.0kg/m3. The total water use efficiency of the AIFI reached more 2.98 kg/m3. Although the kel yields of the AIFI remained to be more than 8000kg/ha in the two years, the irrigated water amounts declined from 3250m3/ha to 1575m3/ha. Thus the AIFI could save irrigation water by more than 33.3%, but did not severely reduce the c yields. The wetting-drying altation of the AIFI could stimulate the root growth, increase the root density and enhance the balanced root distribution; the dryness of partial root zone formed by the AIFI stimulated the roots to form the root signals to regulate the stomata openness, reduce the evaporation through the clearances among the plants, raise the evaporation efficiency and save the irrigation water.