A touch display system and a control method thereof are provided. The touch display system includes a touch display panel and a controller. The touch display panel includes a touch area and is configured to sense a touch operation of a user. The controller is coupled with the touch display panel and is configured to acquire a physical sign information of the user who is to operate the touch display panel, and adjust a touch range for the user to perform the touch operation in the touch area according to the physical sign information of the user.