An apparatus for converting color temperature in a color display system, and a method thereof. A first color temperature converting factor unit has a first color temperature converting factors for converting a first predetermined color temperature to a particular color temperature, and a second color temperature converting factor unit has a first color temperature converting factors for converting the particular color temperature to a second predetermined color temperature. A color temperature converting factor creating unit makes a color temperature converting factor for converting an input color temperature to an aiming color temperature based on a first converting factor selected from the first color temperature converting factors according to the input color temperature and based on a second converting factor selected from the second color temperature converting factors according to the input aiming color temperature.