A color display system comprises a color signal source, a buffer unit, a storage unit, an enlarging module, a comprising unit, and a multi-functional comparing unit. By the multi-functional comparing unit comparing an OD enlarged value of the enlarging module, a grayscale of the color signal source, and a signal for OD technique free of the comparing unit and then submitting a result, either the grayscale of the now-frame or the OD enlarged value, the color display system can fast and accurate response and display grayscales of colors. The color display system is applicable to use for LCD (liquid crystal display), PDP (Plasma Display Panel), TFT, OLED (Organic Electro Luminesence Display), and PLED (Polymer OLED).