An air conditioning system, comprising: an air handling unit AHU configured to control outdoor air that is externally supplied, exhaust air that is discharged from indoors to outdoors, and return air that is circulated indoors and supplied again, control the outdoor air or mixed air of the return air and the outdoor air at a set temperature, and supply cool/warm supply air indoors; at least one outdoor unit configured to supply a refrigerant to the AHU; a controller configured to control the AHU through communication with the outdoor unit; and an interface unit configured to operate as an input/output unit of the controller, wherein the interface unit is configured to display control menus and a monitoring menus in accordance with functions of the AHU changed according to a configuration of a plurality of devices forming the AHU, display setting menus for the plurality of devices forming the AHU, set basis data for controlling the plurality of the devices in response to data received through the setting menus, input the set basis data to the controller, characterized in that: the interface unit is configured to classify the functions into functions of the AHU that are executable and functions of the AHU that are not executable in accordance with the configuration of the plurality of devices, and display the classified functions, and wherein menu items for the functions that are not executable are deactivated and displayed or removed. an air handling unit AHU configured to control outdoor air that is externally supplied, exhaust air that is discharged from indoors to outdoors, and return air that is circulated indoors and supplied again, control the outdoor air or mixed air of the return air and the outdoor air at a set temperature, and supply cool/warm supply air indoors; at least one outdoor unit configured to supply a refrigerant to the AHU; a controller configured to control the AHU through communication with the outdoor unit; and an interface unit configured to operate as an input/output unit of the controller, wherein the interface unit is configured to display control menus and a monitoring menus in accordance with functions of the AHU changed according to a configuration of a plurality of devices forming the AHU, display setting menus for the plurality of devices forming the AHU, set basis data for controlling the plurality of the devices in response to data received through the setting menus, input the set basis data to the controller, display control menus and a monitoring menus in accordance with functions of the AHU changed according to a configuration of a plurality of devices forming the AHU, display setting menus for the plurality of devices forming the AHU, set basis data for controlling the plurality of the devices in response to data received through the setting menus, input the set basis data to the controller, characterized in that: the interface unit is configured to classify the functions into functions of the AHU that are executable and functions of the AHU that are not executable in accordance with the configuration of the plurality of devices, and display the classified functions, and wherein menu items for the functions that are not executable are deactivated and displayed or removed. the interface unit is configured to classify the functions into functions of the AHU that are executable and functions of the AHU that are not executable in accordance with the configuration of the plurality of devices, and display the classified functions, and wherein menu items for the functions that are not executable are deactivated and displayed or removed.