During the process of water transmission and distribution, many medium and large irrigation districts have the problem of improper water level convergence, and field surface elevation exists ups and downs, so part of the field surface can't be moisturized or submerged during irrigation. So the concept of the space irrigation rate was put forward in this study, and the relation between space irrigation rates and channel canal water level was studied by using three-dimensional analysis capabilities of GIS. Analysis showed that the relationship between the space irrigation rates and canal water level was consistent with the Logistic curve. Logistic curve parameters of Chuanhang Irrigation District Branch One were obtained , and water level of Branch One headwork and water level of canal headwork, which was required for different space irrigation rates, were confirmed. So the underlying data of regulation of water level in irrigation district with were provided.