In ground source heat pump (GSHP) system, computational fluid dynamics (CFD) is commonly used to conduct simulation analysis of its operating characteristics. Particularly, ground heat exchanger (GHE) is the most core component of GSHP system, and the heat transfer characteristics of which with soil around will directly affect the efficiency of the entire system. Thus, CFD is always applied to predict the process of heat transfer around GHE and its influence on heat exchange process. In this chapter, a 3-D numerical model considering dynamic surface condition and initial soil temperature distribution is developed to investigate the thermal performance of helix ground heat exchanger (HGHE) on basis of CFD, and the main influencing factor (inlet water temperature) is studied with the established model. In addition, the experimental investigation is carried out to verify the accuracy of the model. The results are of great significance for exploring the application of CFD in GSHP system.