The present research aimed to improve the performance of a parallel-flox-type classifier by employing particle wall collision, which is referred to here as impact effect. The numerical methods employed include a k epsilon E two-equation turbulent model for the gas phase, the random simulation technique and the two-way method for coupling the interaction between the gas and solid phases. The partial classification efficiency from numerical analysis was tested experimental by. They data showed the same trends as the numerical analysis though some discrepancy was found. The main reason for this discrepancy was suggested to be the underevaluation of slip velocity between particle and gas in the numerical analysis. A modification factor of classifier free time coefficient was suggested as a mens to correct this underevaluation and bring about agreement with the experimental results. The method of adding a small impact body at main nozzle was shown by numerical and experimental results to enhance the impact effect and improve the performance of the classifier.