The area of general restaurants is relatively large, so it is suggested to install a central fresh air system, which should be carried out at the same time as the renovation. The central fresh air system is to install the main engine on the ceiling of the blank room, connect it with the main engine by arranging air supply pipes (air supply) and return air pipes (air exhaust), and arrange air outlets at the required positions. The labor special fresh air system can effectively transport the filtered fresh air to the required areas, and the design of one row of pipes can greatly increase the indoor air mobility and achieve good ventilation.