The invention discloses a blade gear ring rotor air engine and a circulating system. The blade gear ring rotor air engine comprises an engine shell, an engine air inlet, an air cylinder, engine exhaust outlets, a blade gear ring rotor, a gear ring rotor inner gear, a transmission gear I, a transmission gear shaft I, a bearing I, a transmission gear II, a transmission gear shaft II, a bearing II, an output shaft gear, an output shaft, a transmission gear support I, a transmission gear support II, a bracket bearing I, a bracket bearing II, an output shaft bearing I, an output shaft bearing II, an engine cover plate I, an engine cover plate II and blades. The invention further provides a circulating system comprising the blade gear ring rotor air engine. The blade gear ring rotor air engine and the circulating system have the characteristics of being high in efficiency, low in air consumption, large in power, high in rotating speed and the like, and capable of being widely applied to agriculture and industrial engineering such as the power fields of transportation automobiles, ships, air-driven generators and air driven power stations.