A user interface system for a vehicle, comprising: a detachable interface apparatus detachably attached to any one of a plurality of display units provided in the vehicle; and a user interface apparatus provided in the vehicle, comprising: the plurality of display units, and a processor configured to, when it is determined that the detachable interface apparatus is attached to any one of the plurality of display units, display a preset user menu corresponding to a type of a selected display unit, to which the detachable interface apparatus is attached, on the selected display unit, characterized in that, the user interface apparatus further comprises an interface unit, and the processor is further configured to: when it is determined, based on vehicle state information acquired through the interface unit, that the vehicle is in an autonomous mode, output a first menu to the detachable interface apparatus which is separate from the plurality of display units; and when it is determined, based on vehicle state information acquired through the interface unit, that the vehicle is in a manual mode, deactivate the detachable interface apparatus which is separate from the plurality of display units. a detachable interface apparatus detachably attached to any one of a plurality of display units provided in the vehicle; and a user interface apparatus provided in the vehicle, comprising: the plurality of display units, and a processor configured to, when it is determined that the detachable interface apparatus is attached to any one of the plurality of display units, display a preset user menu corresponding to a type of a selected display unit, to which the detachable interface apparatus is attached, on the selected display unit, characterized in that, the user interface apparatus further comprises an interface unit, and the processor is further configured to: when it is determined, based on vehicle state information acquired through the interface unit, that the vehicle is in an autonomous mode, output a first menu to the detachable interface apparatus which is separate from the plurality of display units; and when it is determined, based on vehicle state information acquired through the interface unit, that the vehicle is in a manual mode, deactivate the detachable interface apparatus which is separate from the plurality of display units. the plurality of display units, and a processor configured to, when it is determined that the detachable interface apparatus is attached to any one of the plurality of display units, display a preset user menu corresponding to a type of a selected display unit, to which the detachable interface apparatus is attached, on the selected display unit, characterized in that, the user interface apparatus further comprises an interface unit, and the processor is further configured to: when it is determined, based on vehicle state information acquired through the interface unit, that the vehicle is in an autonomous mode, output a first menu to the detachable interface apparatus which is separate from the plurality of display units; and when it is determined, based on vehicle state information acquired through the interface unit, that the vehicle is in a manual mode, deactivate the detachable interface apparatus which is separate from the plurality of display units. when it is determined, based on vehicle state information acquired through the interface unit, that the vehicle is in an autonomous mode, output a first menu to the detachable interface apparatus which is separate from the plurality of display units; and when it is determined, based on vehicle state information acquired through the interface unit, that the vehicle is in a manual mode, deactivate the detachable interface apparatus which is separate from the plurality of display units.