A touch display device including multiple data lines, multiple scan lines and a substrate is provided. The data lines and the scan lines are formed on the substrate. The touch display device includes multiple pixel elements arranged in the form of a pixel array and coupled to the corresponding data lines and the corresponding scan lines and multiple touch sensor electrodes arranged in the form of a sensor array. The touch display device further includes a touch gate pad formed on the substrate and multiple first switch transistors. Each first switch transistors includes a first end, a second end and a control end. The first end is coupled to one of the touch sensor electrodes in a first column of the touch sensor electrodes, and a touch display driver. The second end is coupled to a first test pad. The control end is coupled to the touch gate pad.