Abstract: Based on the unique extreme environment of the moon, a combined cooling and power (CCP) system for lunar base was designed and subsequently improved by selecting appropriate mixed working fluids. Three suitable mixed organic working fluids were screened for the CCP system, and a comparative analysis was conducted between the systems utilizing mixed and pure working fluids to highlight the advantages of the mixed-fluid system. Finally, the characteristic parameters of the CCP system based on mixed working fluids were calculated and analyzed. The results show that the maximum net output power of the mixed-fluid system is 12%-21% higher than that of the pure-fluid system, and the maximum exergy efficiency is about 3% higher. Furthermore, the analysis demonstrates that the CCP system satisfies the lunar base's requirements for heat dissipation, cooling and energy saving under four typical operating conditions. During the lunar night, the maximum power generation is 1 128.29 W, and the maximum cooling capacity is 13.32 kW. While during the lunar day, the maximum power generation is 1 471.66 W, and the maximum cooling capacity is 13.36 kW.