This article consists of four sections. The first section aims at probing the use of the history of cinnabar in traditional China and the intrinsic meaning of the use of cinnabar. The second section explores the content and nature of external alchemy. We find the most important purpose of external alchemy is to grasp the basic strength of the universe. The metaphysics of external alchemy could be called experimental metaphysics. The third section aims at probing the content and nature of internal alchemy. We also find the most important purpose of internal alchemy is to grasp the basic \ strength of the universe. The metaphysics of internal alchemy could be ; called mystical metaphysics. The biggest difference of external alchemy and internal alchemy is method and material. The last section compares the simi-; larities and differences, and advantages and disadvantages, of experimental '? metaphysics and mystical metaphysics. We think mystical metaphysics is ?superior to experimental metaphysics. We can obtain important enlighten-l ment from the exploration of the metaphysics of internal alchemy.