This paper introduces the first ethylene process in China based on LNG cold energy utilization, which uses methanol as an intermediate refrigerant for indirect heat exchange, thereby realizing the mutual supply of cold and heat between the cooling capacity in the LNG receiving station and the ethylene plant. The cascade utilization of refrigerant temperature replaces some users of the original propylene and ethylene compressor, greatly reducing the power consumption of refrigeration compressors. The energy consumption of separation system is reduced by about 11％, and the comprehensive energy consumption of ethylene plant is as low as 497 kgEO/t ethylene. The methanol refrigerant system will be the key to the smooth operation of ethylene plant. Through the analysis of refrigerant start-up and typical accident conditions, some ideas are provided for the operation of ethylene plant.