As an important dynamic classifier, turbo air classifiers are widely used in various fields. To improve the classification performance of turbo air classifiers, a novel rotor cage with non-radial arc blades is designed by analyzing the influence of the rotor blade profile and the installed angle on the flow field in a turbo air classifier. Numerical simulations by ANSYS-FLUENT 14.5, as well as material classification experiments, are implemented to verify the new design. Simulation results indicate the significant improvement of flow field distribution in the rotor cage with non-radial arc blades. The incidence angle at the inlet of the rotor cage decreases significantly. Airflow streamlines match the profile of the non-radial arc rotor blade perfectly, and no air vortex is present in the channels of the rotor cage. The material classification experiment results demonstrate that the classification accuracy increases by 10.6%–40.8%, and the fine powder yield increases by 12.5%–40.1%, with an almost changeless cut size. The experimental results agree with the simulation results, thus verifying the feasibility of the modified rotor blades in practice. This design provides a theoretical guidance for the structure improvement of different types of classifiers with a rotor cage.