Abstract: The present invention relates to an ink ribbon positioning system of a color printer for identifying a position of a color ink ribbon of the color printer. The ink ribbon is windingly installed inside an ink ribbon box comprising a plurality of dye blocks. Each of the dye blocks comprises a plurality of transparent color frames, and the color frames are used for storing different color dyes. The ink ribbon positioning system comprises a light source installed at one side of the ink ribbon for emitting a color light beam through the ink ribbon, an optical sensor for detecting the light beam and generating a corresponding output voltage, and an identification device for identifying positions of a dye block of the ink ribbon and color frames inside the dye block according to output voltages generated by the optical sensor and generating corresponding position signals. The color printer further comprises a thermal print head and a control circuit.