Ground Source Heat Pump(GSHP) is a widely used technology. GSHP with closed loop vertical Ground Coupled Heat Exchanger(GCHE) is a very common type and has very stable performance, which can be used in building’s air conditioning or hot/cold water system to save energy. However, the research of this type of GSHP is still lack in Taiwan. This paper, with the purpose to find proper way to utilize the GSHP technology, provides the average geothermal temperature of different areas in Taiwan and analyzes the heat exchange properties of closed loop vertical GCHE on the basis of series of experiments launched in Tainan, where 4 Boreholes with 60m depth were drilled for a six-month research. Conclusions of this study include: 1) underground temperature of experimental site is a little high, average temperature is 27.56℃ in 53.5m depth; 2) heat in soil diffuses very slowly, and the accumulation of heat causes obvious rise of the underground temperature; 3) in experiments, underground temperature changes obviously in first 5-6 hours but keeps approximately the same after 20-23 hours; 4) under certain conditions, heat exchange efficiency of double-U type of GCHE is better than single-U type; 5) cold energy in winter can be used to restore thermal balance of ground with high efficiency.