An airport surface traffic system is provided which detects targets moving on an airport surface and automatically adds ID codes thereby reduces the controlling duties of an air traffic controller and elevates safety of an aviation control. An airport surface traffic system comprises airport surface monitoring radars which detects targets moving on an airport surface, ASDE target detector which detects targets by an output signal of the airport surface monitoring radars, a second monitoring radar which receives response signals from airplanes and from an airport monitoring radar which controls airport, ASR/SSR target detector which detects targets, ID code addition apparatus which adds an ID code to targets based on a signal from FDP which stores flight schedule data of airplanes and a multi-function display which displays targets.