On the basis of qualitatively analyzing the recharge, run-off and discharge conditions of ground water in Gaoqing Plain, authors propose that it should be regarded as a principle of ground water resource evaluation to transform useless evaporation of phreatic water into avail-able water resource. Then the mathematical model describing two-dimensional unsteady subsur-face flow in the heterogeneous aquifer was established in accordance with the hydrogeological conditions. Also rational parameters were selected in the light of a vast amount of actual materi-als. Meanwhile finite element method was employed to quantitatively predict the water table and buried depth after different exploitation schemes.On the premise of guaranteeing the water quantity balance and by comparing the different water table depths after all plans, the conclusions how to rather rationally extract water re-sources were reached based on the two different hypothetic precipitation series: (1) the precipi-tation series from 1975 to 1989; and (2) the average precipitation series coming from several decades.Subject to the hypothesis (1), the allowable exploitation in the phreatic aquifer is about 142. 5 millions cubic meters per year in case that the Yellow River keep flowing and can be chan-neled from it for irrigation, while 128. 0 millions cubic meters per year in case that the Yellow River dry up. Similarly, subject to the hypothesis (2), the allowable exploitation is about 168- 4 millions cubic meters per year in case the Yellow River keeps flowing, while 140. 0 millions cubic meters in case the Yellow River dries up.The research results manifest that the ground water is rather abundant and the extraction in current situation accounts for about one forth of the allowable exploitation of the phreatic water. As a result the phreatic aquifer has great potentialities for exploitation. At the same time, the water table would become lower and the evaporation discharge become smaller with the exploitation of ground water, which would be bound to produce positive environmental effects.