Dust particles include mold spores or excrement and corpses of the mite and so on. There is a high possibility of allergic reactions in child whose breathing zone is near the floor. Ventilation is one of the best ways to remove dust particles. It is important to know the removal efficiency of dust particles in different ventilation strategies room. In this study, two kinds of ventilation strategies were considered, namely ceiling exhaust and slit exhaust. In the experiments, comparison of the number of particle shows that the ceiling exhaust was a little higher than the slit exhaust. Computational fluid dynamics (CFD) simulations concerning diffusion fields completed. In the simulations, the removal efficiencies of ceiling exhaust and slit exhaust were found 81.5 and 85.8 %, respectively. From the data we concluded that slit exhaust ventilation strategy will produce less dust particles comparing with ceiling exhaust ventilation strategy in room.