When the ground coupled heat pump (GCHP) system is used for cooling load dominated buildings, the heat rejected into the ground will accumulate around the ground heat exchangers, which results in degradation of system performance. One of the available options to resolve this problem is to utilize the hybrid ground coupled heat pump (HGCHP) system to reject the accumulated heat by supplemental heat rejecter. In order to investigate the performance of HGCHP system operated with different control strategies for cooling service, a practical analytical simulation model is developed by analyzing and modeling the heat transfer processes of its main components on short time step basis, and a computer program is produced based on this model for predicting the operating parameters of the HGCHP system. Besides, detailed on-site measurements are carried out on a HGCHP test rig. The operation parameters of the HGCHP system operated with four different control strategies are tested and simulated. The optimal control strategy of the HGCHP test rig is proposed and the accuracy of the HGCHP system simulation model is validated by experimental results. The advantage for using the proper HGCHP system is obvious in terms of energy efficiency compared with the conventional GCHP system.