Underground aquifer energy-stored air conditioner system is a renewable and sustainable energy system built under the conditions of extraction-injection equilibrium of geothermal water.The principle of underground aquifer energy-stored air conditioner system is introduced,and its energy self-circulation system is analyzed.A 3-dimensional mathematical model of non-steady flow field is established by use of law of conservation of mass,law of conservation of momentum and law of inversion & conservation of energy.Combining with a practical example,by computer simulation the diagrams of isothermal surface of the energy-stored aquifers during heating period and cooling period are obtained,so the distance between extracting well and injecting well is determined.