Abstract: Propane-mixed refrigerant cycle dominates the base-load liquefaction plant for its advantages of saving investment, simple process and fewer units. The HYSYS simulation is carried out and the effects of process parameters, such as gas pressure, mixed refrigerant pressures and mixed refrigerant composition on the refrigerating capacity and energy consumption of the compressors and water cooler are analyzed. The simulation results show that: increasing the gas pressure and reducing the methane content of the refrigerant can not only enhance its refrigerating capacity but also reduce the energy consumption; and increasing the pressure of the low pressure refrigerant and decreasing the pressure of the high pressure refrigerant can reduce the energy consumption but weaken the refrigerating capacity. A scheme of enhancing the refrigerant flow and reducing the methane content is proposed to make up for the reduction of the refrigerating capacity.