Abstract. As a high efficiency, low consumption and clean energy, ground source heat pump technology has been pay more and more attention, the number of installation of system is growing rapidly. However, the use of geothermal resources is still extensive at this stage. Effective methods are pure in obtaining thermal physical parameters of geothermal wells around. In-situ thermal response testing is close to the real use of heat pumps, when injecting in or extracting heat from geothermal wells, the testing equipment will collect data, and then thermal physical parameters will be accurately calculate. This paper introduce a thermal response testing equipment, the equipment will add a constant cold or heat to geothermal well, circulating heat flow and pressure data is collected as well as temperature. And then thermal physical parameters of formation and heat exchanging performance are calculated.