Abstract: Abstract: Ground source heat pump (GSHP) has been very popular for space heating and cooling due to its high energy efficiency and low operating cost and thus it is still a very important research subject. Ground heat exchanger is a key component of GSHP. The comprehensive understanding about the heat transfer characteristic of the ground heat exchangers and the soil temperature distribution around the ground heat exchangers is crucial to the performance of GSHP and a large number of researches were carried out, because the operating conditions of GSHP were related closely to the soil temperature field around the ground heat exchangers. Besides, the heat imbalance of GSHP has been become a serious problem, because the amount of heat extracted from and rejected to the soil is usually not equal. It is an especially obvious problem for heating-dominated buildings in the cold and severely cold regions. So, the temperature recovery ability of soil has attracted wide attention. This paper presents the study of the temperature variation characteristics of soil around the ground heat exchangers in the process of heat storage and release of GSHP in the center of Inner Mongolia, China. Based on the finite element method, two-dimensional physical and mathematical models of transient heat transfer were established for the soil around the vertical U-tube ground heat exchanger. The heat storage, heat release and the coupling process were studied on the basis of experimental verification. The variation laws of thermal influencing radius, heat exchange of unit pipe and soil temperature with the operation time and operation mode of GSHP were revealed. The soil heat equilibrium problems in the heat storage, heat release and the coupling process were discussed. The influence of fluid inlet velocity, inlet temperature, soil types and GSHP operation model on the soil temperature field were explored. The results indicated that the thermal influencing radius increased with the increase of operation time and became gentle eventually. With the 25 and 28 days running-time of GSHP, thermal influencing radius is 3.3 and 3.4 m, respectively. The fluid inlet temperature has a great influence on the thermal influencing radius and heat flux of unit pipe, while the fluid inlet velocity has a small impact on these. The fluid inlet temperature and inlet velocity are 40, 60 ℃ and 0.6, 1.2 m/s, respectively. And the corresponding thermal influencing radius is 3.7, 4.5 and 3.5, 3.6 m. The proper intermittent operation mode could improve the heat transfer rate and the temperature recovery ability of soil around the ground heat exchanger. The recovery time and recovery effect of soil temperature were better with the increase of the thermal conductivity of soil. With the running time of 84 h (heat rejection of 12 hour and recovery of 72 hour), the soil temperature is 9.3℃ with a thermal conductivity of 3.1 W/( m×K) (the initial temperature of soil is 9.5℃). In addition, the unequal heat transfer had a great influence on the soil heat balance in the coupling mode of heat storage and release. The experimental validation indicated that enough accuracy could be achieved using the model developed in this study with a maximum difference of 5.35%.