The C₃/MRC liquefaction process is designed for Synthetic Natural Gas (SNG). Analyzed are effects of temperature distribution of different cold boxes in propane refrigerant cycles and mixed refrigerant cycles on liquefaction power consumption and effects of SNG throttling pressure on liquefaction rate and compared is liquefaction power consumption of feed gases with different components. Study results show that C₃/MRC liquefaction process applies to SNG and thermal fluid outlet temperatures of cold boxes have great effect on liquefaction power consumption. Additionally, H₂ content in BOG gas increases as after-throttling pressure grows and the unit consumption of liquefied SNG is higher than natural gas from gas field. The liquefaction rate of SNG after optimization can reach 94.95% with a power consumption rate of 0.34kW • h/Kg LNG.