To make clear the groundwater of the main replenishment resources and that rely for existence of desert plant;According to the data analysis of the groundwater experiment field in Yulin,and mechanism analysis of the condensation in the desert pool of the North Area of Shaanxi.The characteristic of the precipitation intercepted by groundwater are studied;and the formula of the calculation condensation is to deduce out,and pass to experiment to proceeds to that formula the verification;it is to the leading meaning that development of groundwater and to have got the importance with the water and soil conservation in that regions.