A minitype GSHP system was designed and installed in the green energy building of Shanghai Jiao tong University for the purpose of satisfying the thermal environment of a meeting room with the covered area of 180 m². The rated cooling capacity of the heat pump is 22.3 kW with the electricity consumption of 5.3 kW. Correspondingly, the rated heating capacity and electricity consumption in heating mode is 29.5 kW and 6.9 kW, respectively. The ground heat exchanger consists of 9 vertical boreholes. There is a single U-tube with the diameter of 32 mm in each borehole. The whole length of the U-tube is 580 m. The experimental investigation was carried out in both cooling mode and heating mode. After one year, the average temperature of soil was about 18 °C, which is nearly the same as the original soil temperature. The experimental results are instructive to the design and operation of GSHP systems in Shanghai and other cities with similar climatic feature.