In this paper, a ground heat source cooling system based on a novel underground heat exchanger is proposed for cooling of a Base Transceiver Station (BTS) in the scope of KC05.21/16-20 project entitled “Research, design and manufacture geothermal cooling systems for Base Transceiver Station”. Compared to traditional underground heat exchanger, the perforated borehole tube is used to improve the heat transfer efficiency by favorizing the interaction between ground water flow and hot water flow in U-type tube. Since the heat transfer from the cooling water and the infinity soil, which is impacted by the soil structure and the groundwater accumulated in the void space, is complicated, the analytical computation is not suitable. The Computational Fluid Dynamics (CFD) model of underground U-type heat exchanger was developed to benchmarking the heat transfer efficiency. The influence of flow configurations and of U-type tube length on the heat load and overall thermal resistance were investigated.