The invention discloses an airflow engine. A plurality of wheel part level bowl wrapping rolling balls are indirectly arranged on a wheel part level skeleton ring at the periphery of a fluid density thinning chamber formed by special-shaped flow gathering drive blades radially arranged at the periphery between an outlet of an entrance neck and a skeleton ring; a plurality of tail part level bowl wrapping rolling balls are indirectly arranged on tail part level support driving blades which are arranged between the skeleton ring and a shaft sleeve on a corresponding center shaft respectively to form a flow gathering drive impeller; under the action of a pressure difference before and behind the entrance neck, a part of an expanded air flow with a certain flow rate expands forward and flows out from gap passages of the fluid density thinning chamber support driving blades, the other part of the expanded air flow expands all around and flows out from gap passages of the special-shaped flow gathering drive blades at the periphery, the expanded air flow generates the effect force to the flow gathering drive blades at the periphery and the support driving blades to push the flow gathering drive blades to carry out circumferential movement and drive the shaft sleeve and the shaft installed in the shaft sleeve to rotate in a bearing installed in a flange frame, and mechanical work output to the external is obtained on the shaft of the airflow engine. By adopting the design scheme of the invention, the utilization ratio and the effect rate of the expanded air flow are increased, and fuel oil, fuel gas and air resources are saved.