Under the background of carbon peak and carbon neutrality in China, oil and gas enterprises are responsible for the effective recycling of high-concentration carbon dioxide emission sources. Since the carbon dioxide liquefaction and recovery unit of Songnan Gas Field was put into operation in 2011, it has not reached the design capacity, and the stable production capacity can only reach 30% of the design capacity due to unstable compressor operation, low liquefaction pressure, insufficient cold supply and other reasons. In order to improve the recovery and utilization rate of carbon dioxide resource, Aspen HYSYS software was used to simulate and optimize the carbon dioxide liquefaction recovery process. After process optimization, the actual liquefaction production capacity was increased by 81%, and the carbon dioxide resource in Songnan Gas Field was fully recycled. The research results can provide the optimization direction and theoretical basis for the further optimization and upgrading of carbon dioxide liquefaction and recovery unit.