A ground thermal response testing system is developed independently on the principle of constant heating flux.Through the method of field testing,it's summed up that the relationship during the power of heating,flow rate of circulating water in the pipe and import and export water temperature of buried pipe.The thermal properties of soil are determined by the line source model.The results show that it is very important to improve the thermal conductivity for its original temperature.The thermal conductivity of the soil tends to be constant after 50 hours and converges to 3.109 W/(m·℃) under the condition of the undisturbed soil temperature and a given PE pipe.The soil thermal conductivity at the average of 3.489 W/(m·℃).It is provided for ground source heat pump system for theoretical basis.