Abstract: To investigate the heat transfer characteristics of the pump-driven loop heat pipe using R32 to replace R22, an experimental unit of pump-driven loop heat pipe system was built to study the variation of cooling capacity and energy efficiency ratio (EER) of the system by using two refrigerants under different indoor and outdoor temperature differences and different mass flow rates of refrigerants. The performances of different refrigerants were analyzed and compared. Results show that the cooling capacity and EER of R32 unit is higher than that of R22 unit under all experimental conditions, and according to the energy-saving analysis, the starting temperature, running time and average EER of the unit using different refrigerants were contrasted, showing that R32 has the advantages over R22 on energy saving. Meanwhile, R32 unit has the problem of insufficient feed liquid when pump frequencies are low under outdoor high temperature.