Abstract: Refrigerating system used on aircraft can provide refrigeration for electronic equipments. Because of the special characters of aircraft pod, there are many differences on framework and working theory between refrigerating system used on aircraft pod and the one used on normal aircraft. Several air cycle refrigerating schemes designed for aircraft pod were introduced. Design concepts, working theories of a reverse bootstrap air cycle refrigerating system driven by 2kW-powered high-speed electric machine were described. Component structural design methods were discussed. Refrigerating performance and performance penalty calculations were given. The results show that the new system has a compact structure and low power consumption. It works reliably and can increase the refrigerating performance. This system is affected by aircraft flight states lightly and can provide cooling capacity when the aircraft is on the ground. It's a promising environmental control system for aircraft pod.