Yi-ology occupies an extremely important position in the cultural history of China and has a far-reaching impact on the development of traditional Chinese medicine. The famous doctors in China attach great importance to the study of Yi-ology. Sun Simiao said in the Tang Dynasty that "I don't know the easy, so I don't cure too much". Therefore, it points out the guiding role of Yi-ology in medicine. Zhang Jingyue in the Ming Dynasty put forward more systematically: "The way of heaven and earth, with Yin and Yang to support a hundred skeletons. Easy, easy, with the wonderful movement of yin and yang; Doctor, meaning is also in harmony with yin and yang. Although Yin and Yang have been recorded in Neijing, the changes are not much different from those in Zhouyi. Therefore, heaven and man are one, and some yin and yang are also; Drugs can easily work from the same source, so they change. Non-medical scholars are not proficient in Yi. However, those who are proficient in Yi Li have great potential in the theory of traditional Chinese medicine. Doctors are easy to communicate and complement each other. This is no accident.