A touch display device includes a main body, a detecting module and a touch display module. The detecting module includes a plurality of sensing elements for sensing a touch position of a user at the main body and providing a touch signal to the detecting module. The touch display module is disposed at the main body and electrically connected to the detecting module. The touch display device generates a function control zone corresponding to the touch position in accordance with the touch signal. A control method of a touch display device is disclosed as well. The touch display device and the control method can generate the function control zone corresponding to the touch position by sensing the touch of the user to replace physical hot keys.