Abstract-The performance of collection efficiency of cylindrical inlet-type cyclone separator for relatively low solid loading rate conditions is reported. Cyclone separators usually operate under high solid loading conditions, but the demand of air pollution control at outdoor densely polluting activities as construction sites and application of power generators, it is advantageous to use cyclone separators to control outdoor air pollution by cyclone separators. Grade efficiencies and overall collection efficiencies have been investigated from 0.008g/m 3 to 0.2g/m 3 solid loading rates at 5m/s and 10m/s inlet velocity conditions. Experimental data were compared with two theoretical predictions based on empirical and mechanistic relationships, developed by Smolik and Muschelknautz. To achieve a better understanding of particle separation efficiency, particle cut size diameter for selected loading rate were considered with theoretical approached by Muschelknautz model. Both experimental and theoretical results showed that with the increase of solid loading rate and inlet velocity, the particle collection efficiency of cyclone separator increases.Index Terms-Cut size diameter, cyclone separator, grade efficiency, solid loading rate, swirling flow, overall collection efficiency.