Abstract: Color palette design plays a significant role in visualization for data understanding. To design and select an appropriate color palette, users need to visually compare various color palettes. However, the difficulty of the visual comparison among palettes becomes extremely severe with an increasing number of color palettes and colors. Existing research in color perception reveals that color palette with well-ordered colors can improve the efficiency of visual comparison. Inspired from this finding, we propose an automatic color palette ordering method for color palette design. Specifically, we propose a color ordering optimization equation under the constraints of global order and visual continuity between colors. Based on the color ordering approach, we develop a color design system, which enables efficient color palette selection, global color palette exploration and color palette retrieval. We conduct quantitative experiments and user studies to evaluate the perceptual consistency of our method and its advantages in the palette comparison task.