1. A source driver, comprising: N primary latching circuits, for respectively receiving N pixel data, wherein N is a positive integer; a multiplexing device, coupled to the N primary latching circuits, for controlling signal transmitting routes of the N primary latching circuits; N digital-to-analog converting circuits, respectively having positive or negative signal outputs, each digital-to-analog converting circuit having a signal output polarity different from a signal output polarity of an adjacent digital-to-analog converting circuit, the N digital-to-analog converting circuits respectively generating N driving voltage signals according to the N pixel data; a switching device, coupled to the N digital-to-analog converting circuits, for controlling signal transmitting routes of the N digital-to-analog converting circuits; and N output circuits, for receiving the N driving voltage signals, and outputting N source driving signals to N pixels, successively; wherein the multiplexing device and the switching device alternatively switch polarities of a plurality of specific source driving signals respectively output by a plurality of adjacent output circuits within the N output circuits according to a polarity switching signal, respectively, where: the polarities of the specific source driving signals are positive, negative, negative and positive during a first period, respectively; and the polarities of the specific source driving signals are negative, positive, positive and negative during a second period, respectively; wherein during the first period, the multiplexing device and the switching device establish following signal transmitting routes: the multiplexing device establishing following signal transmitting routes: a signal transmitting route between a first primary latching circuit and a first digital-to-analog converting circuit, a signal transmitting route between a second primary latching circuit and a second digital-to-analog converting circuit, a signal transmitting route between a third primary latching circuit and a fourth digital-to-analog converting circuit, and a signal transmitting route between a fourth primary latching circuit and a third digital-to-analog converting circuit; and the switching device establishing following signal transmitting routes: a signal transmitting route between the first digital-to-analog converting circuit and the first output circuit, a signal transmitting route between the second digital-to-analog converting circuit and the second output circuit, a signal transmitting route between the third digital-to-analog converting circuit and the fourth output circuit, and a signal transmitting route between the fourth digital-to-analog converting circuit and the third output circuit; wherein the first primary latching circuit to the fourth primary latching circuit, the first digital-to-analog converting circuit to the fourth digital-to-analog converting circuit and the first output circuit to the fourth output circuit are respective adjacent to one another, and the first output circuit to the fourth output circuit respectively output the specific source driving signals; and wherein during the second period: the multiplexing device establishes following signal transmitting routes: a signal transmitting route between the first primary latching circuit and the second digital-to-analog converting circuit, a signal transmitting route between the second primary latching circuit and the first digital-to-analog converting circuit, a signal transmitting route between the third primary latching circuit and the third digital-to-analog converting circuit, and a signal transmitting route between the fourth primary latching circuit and the fourth digital-to-analog converting circuit; and the switching device establishes following signal transmitting routes: a signal transmitting route between the first digital-to-analog converting circuit and the second output circuit, a signal transmitting route between the second digital-to-analog converting circuit and the first output circuit, a signal transmitting route between the third digital-to-analog converting circuit and the third output circuit, and a signal transmitting route between the fourth digital-to-analog converting circuit and the fourth output circuit.