Abstract: Geothermal water belongs to confined water, and its storage capacity includes volume storage capacity and elastic storage capacity. When the water level is above the aquifer roof, the exploited geothermal water can only be elastic storage capacity. The recoverable amount of geothermal water was calculated by mining coefficient method and analytical method in the evaluation of regional geothermal resources in Hebei Plain, which has a huge difference with elastic storage amount. In order to study the composition of geothermal water exploitation resources and evaluate more accurately the exploitable quantity of geothermal water in the concentrated exploitation area, the author of this paper has adopted the groundwater balance method to calculate the exploitation quantity of geothermal water in Xinji concentrated exploitation area. The results show that lateral recharge is 126×10⁴ m³, accounting for 60.9% of the exploitation resources; the overflow recharge is 19.7×10⁴ m³,accounting for 9.55% of the exploitation resources; the elastic water release is 33.1×10⁴ m³,accounting for 16.1% of the exploitation resources, and the impermeable water release is 27.4×10⁴ m³, accounting for 13.3% of the exploitation resources. The exploitation resources of geothermal water in the concentrated mining area not only come from the elastic water release of thermal reservoir, but also include lateral recharge, overflow recharge and compaction water release. These results are of great significance to the scientific and reasonable development of geothermal resources, and to better control and alleviation of the geological environment problems caused by geothermal water exploitation.