This purpose of this paper is to study the main factors to improve the air cleaning speed according to air-flow type of indoor air cleaner in residential space. This study was attempted CFD simulation method with using the multiple size group model (MUSIG) in order to evaluate indoor air quality and ventilation. As this simulation result, it was found that front-side type discharge of air cleaner is faster about 1.25 times than upward-side type in same velocity condition when residual dust ratio is the 10% level. The simulation results could be used as a base data in order to design the flow pattern for comfortable indoor air quality environment in a residential space.