A method for driving a liquid crystal display (LCD) includes receiving image data of each display unit of the LCD in every display period to determine gray levels of the display units, controlling a gate driver of the LCD to scan each of the display units at least twice every display period, controlling a source driver of the LCD to generate a switch signal, controlling the source driver to determine the gray levels of one row of the display units when the switch signal is at a first voltage level, and controlling the source driver to drive one row of the display units to a predetermined gray level status when the switch signal is at a second voltage level.