The cyrogenic separation process of ethylene plant requires the refrigeration system to provide cold energy at different temperature levels, and the low temperature LNG releases large amounts of cold energy during heating and vaporization. This paper studies the cold energy integration of LNG terminal and ethylene plant. It is proposed to use the cold medium carrying LNG cold energy to replace the ethlyene and propylene refrigerants in ethylene plant, so as to reduce the compressor power and reduce the energy consumption of ethylene plant. In a 1,200 kt/a ethlyene plant, -80℃ cold medium is used to replace part of the ethlyene and propylene refrigerants, and the cold medium consumption is about 800 t/h. Compared to the ethlyene plant of the same capacity, the power of propylene refrigeration compressor is reduced by 11,600 kW and the power of ethylene refrigeration compressor is reduced by 1,500 kW, therefore the unit energy comsumption of ethylene plant is reduced by 25 kg EO/t ethylene.