Experimental studies were conducted on the effect of rotor blades in a laboratory-scale mechanical impact mill. The flow fields and particle trajectories in the mechanical mill were also calculated by use of the CFD software Fluent and compared with the experimental results. Calculations of the flow field and particle trajectories in the mill were perform to examine the effect of the number of blades and blade angle on pulverization performance. The impact frequency of particles against walls increases with increasing number of blades. On the other hand, the inclination of blade angle in the direction of rotation prevents coarse particles from passing directly through the pulverizing zone. The impact velocity of particles and the specific energy of particle impaction show a maximum when blades are inclined forward at angles from 15 to 30 degrees. As a result, high performance of product particle size is realized with the forward-inclined blades.