Air-supplying and exhausting devices start at the same time (Warm-up in winter), fresh air enters to the heating air-supplying unit through inlet filter from air inlet, and the processed airflow will be passed by the air-supplying unit to the static pressure chamber on the top of the booth. The airflow will be treated by the filter cotton on the bottom of the chamber and then entered in the painting booth in laminar flow way, which makes the remaining paint mists down along the airflow, avoiding them emission all round.