The purpose of this study is to predict effect of slit exhaust ventilation system on the indoor distribution of house dust with experiments and CFD. The ventilation system includes inlet located at the ceiling and outlet of slit exhaust installed at corner between wall and floor. Experiments and simulations were performed to investigate the flow and diffusion fields that are affected by this slit exhaust ventilation system. The characteristics of airflow with experiments and CFD are generally similar except airflow at the location of impinging flow. Riboflavin particles were used as the house dust. After slit exhaust ventilation system is operated, the decay rate of the particles becomes faster than that before the ventilation system is on, and the particles with diameter of 0.5-3.0 urn in the experimental data and calculated values showed good agreement.