The coloration machanism of Changhua Chicken_Blood Stone hasbeen discussed in this paper on the basis of X-ray diffraction analysis, SEM and electron microprobe analysis. The color of “Tianhuang Dong” is related to the isomorphism of such impurity elements as Fe3+ and Cr3+. The light red color of “Furong Dong" is caused by the isomorphism of Cr3+. The light green color of “Bohe Dong" and the purple color of “Zhusha Dong" are related respectively to the existence of illite and goethite.