Abstract: Based on slice identification and X-ray powder diffraction, the mineral compositions in "Di" of Changhua Chicken Blood Stone are systematically studied in this paper. The research results show that the main minerals in "Di" of Changhua Chicken-Blood Stone are dickite and kaolinite, and minor minerals are alunite, halloysite, quartz and pyrite, et al. The ch ange trend of the mineral compositions of Changhua Chicken Blood Stone is that the amount of dickite decreases gradually and the ones of kaolinite, alunite, halloysite, quartz and pyrite increase from "Dong Di" to "Gang Di". The quality of "Di" of Changhua Chicken-Blood-Stone is closely related to the mineral compositions.