A source driver utilized for a display device and switching between two operational modes includes a reception module for receiving a plurality of display information and a plurality of transmission channels. Each transmission channel includes a register module for receiving one of the plurality of display information; a voltage level transformer for determining a voltage level of the one of display information; a polarization digital-to-analog converter for processing a digital-to-analog operation for the voltage level of the one display information; and an output module for outputting a plurality of voltage levels of the display information. The voltage levels of every two adjacent transmission channels include different polarization of voltage levels, and the output module processes an odd-number switching operation before outputting the plurality of voltage levels.