Based on the operation of a Ground Source Heat Pump (GSHP) in Hefei, the heat exchange of the 100m depth vertical u-shaped pipe buried in the ground was analyzed, and the heat transfer performance, efficiency of the system and temperature variation of the ground were studied experimentally under the typical climate in Hefei. Temperature changes of the field near the heat exchanger after 8h and 24h were analyzed by numerical simulation. Results show that the system has a good performance in winter.