Ammonium perchlorate has been pulverised by an impact mill (air classifier mill) to study the influence of different operating parameters, viz., effect of mill speed, classifier speed, feed rate, and damper opening (suction rate) on the particle size. Further based on the different grinding parameters, an empirical equation has been developed and used for the prediction of particle size. The experimental results indicate that the values are very close to the predicted ones. In addition, particle size distribution has also been studied by applying different model equations and it has been found that Rosin-Rammler model is the most suitable model for this operation.