This paper analyzed the interaction between urbanization and eco-environment in arid area, and then deduced the coupling function and coupling curve between urbanization and eco-environment in arid area systematically. On the base of the coupling function and curve, we analyzed the coupling types and the coupling stages theoretically. Finally, we validated the coupling function, curve, types and stages between urbanization and eco-environment in arid area with an example of Hexi Corridor. Studies showed that the dynamic coupling relation between urbanization and eco-environment is mutual promotion while inter-coercing course. This kind of coupling relation takes on a double-exponential function changing law, and the evolutive track of the interaction between urbanization and eco-environment is a double-exponential curve. During the interactive coupling course between urbanization and eco-environment, nine basic coupling types may be existed, that is rudimentary coordinating type, ecological dominated type, synchro coordinating type, urbanization lagging type, stepwise break-in type, urbanization exorbitant type, fragile ecological type, rudimentary break-in type and unsustainable type. The coupling system of urbanization and eco-environment in arid area will go through five basic coupling stages, namely rudimentary coordinating stage, antagonistic stage, break-in stage, ameliorative stage and high-grade coordinating stage. The interactive coupling course between urbanization and eco-environment of the cities in Hexi Corridor accorded with the double-exponential changing law, and the coupling tracks of the cities taken on a shape of double-exponential curve. Jiayuguan city belongs to stepwise break-in type, and is at its ameliorative stage; Jinchang city belongs to urbanization exorbitant type, and is at its break-in stage; Jiuquan city belongs to ecological dominated type, and is at its antagonistic stage; Zhangye city belongs to synchro coordinating type, and is at its antagonistic stage; Wuwei city belongs to fragile ecological type, and is at its fragile ecological type; Yumen city belongs to rudimentary break-in type, and is at its ameliorative stage; Dunhuang city belongs to fragile ecological type, and is at its antagonistic stage; Hexi Corridor belongs to fragile ecological type, and is at its antagonistic stage.