The terminal box (TB) is one of the key components in variable-air-volume (VAV) systems. The minimum air flow set point of the VAV TB is an important factor to determining thermal comfort, indoor air quality and energy consumption. The newly developed occupancy based air distribution system control presented in this paper resets the minimum air flow set point for each TB based on the actual occupancy of the space served and ASHRAE ventilation standard. Differentiated from existing motion detection sensors on the market, building occupancy sensors count the number of occupants for each room. Occupancy data of each room, each zone and the whole building are collected and transferred to the building automation system (BAS) in real time using a wireless sensor network. The data are then used to determine the minimum air flow set point. This paper presents the system architecture, control strategy and available sensor technology.