Swept blades have been widely used in the transonic fan/compressor of aircraft engines with the aids of 3D CFD simulation since the design concept of controlling the shock structure was firstly proposed and successfully tested by Dr.Wennerstrom in the 1980s.However,some disadvantage phenomenon has also been induced by excessively 3D blade geometries on the structure stress insufficiency,vibration and reliability.Much confusion in the procedure of design practice leading us to recognize a new view on the flow mechanism of sweep aerodynamical induction: the new radial equilibrium established by the influence of inlet circumferential fluctuation(CF) changes the inlet flows of blading and induces the performance modification of axial fans/compressors blade.The view is verified by simplified models through numerical simulation and circumferentially averaged analysis in the present paper.The results show that the CF source items which originate from design parameters,such as the spanwise distributions of the loading and blading geometries,contribute to the changing of averaged incidence spanwise distribution,and further more affect the performance of axial fans/compressors with swept blades. Swept blades have been widely used in the transonic fan / compressor of aircraft engines with the aids of 3D CFD simulation since the design concept of controlling the shock structure was first proposed and successfully tested by Dr. Wennerstrom in the 1980s. However, has also been induced by excessively 3D blade geometries on the structure stress insufficiency, vibration and reliability. Much confusion in the procedure of design practice leading us us recognize a new view on the flow mechanism of sweep aerodynamical induction: the new radial equilibrium established by the influence of inlet circumferential fluctuation (CF) changes the inlet flows of blading and induces the performance modification of axial fans / compressors blade. The view is verified by simplified models through numerical simulation and circumferentially averaged analysis in the present paper. The results show that the CF source items which originate from design parameters, such as the spanwise dis tributions of the loading and blading geometries, contribute to the changing of averaged incidence spanwise distribution, and further more the performance of axial fans / compressors with swept blades.