Abstract: An inland river in arid land can be divided into several landform units,including mounta in area,mountain-front alluvial fan,alluvial plain,belt of transition of oasis and desert,and desert and so on.Mountain-front depressed belt around most in land rivers has huge thick gravel aquifer,which is natural ground reservoir with rich ground runoff.When surface water flows through flood alluvial fan,a large quantity of seepage flow from rivers and canals compensates depressed belt of mounta in front ground reservoir.After runoff flows in to plain area of fine soil from the lower ridge of flood alluvial fan,grain of soil gradually becomes fine which forms a natural ground dam of blocking water while ground runoff is over spilled in the form of spring water after it is blocked.Taking the Pilot Project of Ground Reservo ir in Tailan River as an example,the paper proposed detailed idea of construction ground reservoir of Cross section Kariz wells mounta in front depressed belt on the basis of analysis and research on main technical characteristics of Kariz wells and combined with characteristics of landform and land feature,structure of storage water and water resources transformation.It gives prmiarily exploration of structure design principles on followings of its three parts:feasibility of ground reservoir by construction of Cross section Karizwells and its reservoir system of compensation by diversion of seepage flow,its water collected system of Cross section Kariz wells,and water deliverysys tem of artesian siphon.Depressed ground reservoir is ideal for water resources works for emergency to fight the drought.It explores a new model for prompting water resources utilization efficiency and regulation water united surface water with the ground water based on its research and pilot.