Low temperature cold chain is the top priority of logistics development at this stage. CO2 (carbon dioxide) refrigeration system is widely used. However, the low efficiency of CO2 refrigeration system is the biggest obstacle to its development. In this research work, a novel trans-critical CO2 refrigeration cycle with ejector for cryogenic storage is proposed. The energy and traditional exergy model of the system are established, and the advanced exergy model is established based on the traditional exergy model, and the actual performance of the system is analyzed. The results show that the exergy destruction of each component of the ejector is the largest in the system, and the optimization potential is the highest in both traditional and advanced exergy models. After studying the influence of main parameters in the system cycle on the system performance and performance, it is found that there is an optimum intermediate pressure and gas cooler pressure in the system to maximize the system performance and efficiency. According to the influence of the change of system parameters on the system, it is found that the outlet temperature of gas cooler has the greatest influence on the optimization of ejector.