Color images is always processed in digital image processing, and in most cases have to process color images then can avoid to change a color image into a gray one and also can avoid the error in that process. The color values are need to quantization and calculated the distance of different colors. This is the most important work, without it can not compare the differences between pixels. A good method to describe the distance between colors based on feature detection in color images is given. It enhances the accuracy in feature detection and also can be used in detecting the similarity of color images.