This paper mainly presents an analysis of the effects of the impeller blade geometry on the performance of a turbo pneumatic separator based on the CFD simulations by using Fluent 14.5.0. The simulation results indicate that the air vortex can be eliminated by using the positive bending arc blades with a remarkably small impacting angle. Furthermore, the optimum installation angle range for the positive bending arc blades was studied. The material classification experiment results show that for the positive bending arc blades with the optimum installation angles, the fishhook depth is decreased, the classification accuracy is increased, and the particle size distribution of fine powders is narrowed, especially under the design condition, compared to the straight blades. This suggestion of impeller blade geometry for the turbo pneumatic separator is the important basis for designing this type of separators and improving its classification performances.