A display device is provided, and which includes a display panel; a gate and a source driving circuits, both coupled to the display panel, for driving the display panel; and a timing control circuit, coupled to the gate and the source driving circuits, for controlling the operations of the gate and the source driving circuits, wherein the timing control circuit comprises a personal identification circuit, and the personal identification circuit is used for receiving an input data; decoding a stored image to obtain decoded data; accumulating the decoded data to obtain an accumulated value; adding the accumulated value to the input data to obtain a compared value; setting the display device to operate normally and output images through the display panel when the compared value is identical to an initial value; and displaying a preset frame on the display panel when the compared value is different from the initial value.