This study makes clear Huang Yuan-Yu(黃元御)'s medical thoughts Yi-philosophically. Yi-philosophy(易學) since ancient times is occupied by fundamental problems of various fields of Oriental Science. Confusian Medicine Reseachers of Zhang Jie-Bin(張介賓), Zhang Nan(章楠), Zhu Zhen-Heng(朱震亨) was seriously affected by Yi-philosophy(易學) and Confucianism(儒學). But I don't think that the majority of their medicine theories are occupied by Yi-philosophy(易學) and Confucianism(儒學). But Huang Yuan-Yu(黃元御) studied medicine thoughts on the basis of Tu Shu Yi(圖書易) in almost whole medicine theories and clinical contents. Therefore this study researched medical thinkings of Huang Yuan-Yu(黃元御) on Yi-philosophical medical viewpoint Tu Shu Yi(圖書易)-scientifically. Especially in this paper the author examined a characteristic point in medical thoughts of Huang Yuan-Yu(黃元御), the difference of existing medicine on Nei-Jing(內經) and Yi-medicine of Huang Yuan-Yu(黃元御), a commonness of medicine principles of Huang Yuan-Yu(黃元御) and Li Ji-Ma(李濟馬)), medicine theories of Huang Yuan-Yu(黃元御) on Tu Shu Yi(圖書易) and a background of Yi-philosophical medical standpoint. The results was summarized as follows; First, Huang Yuan-Yu(黃元御)'s standpoint on five phase is that the relation of earth and wood fire metal water is form and use(體用). Huang Yuan-Yu(黃元御) insists that the earth represents existence itself and wood fire metal water is concepts that represents actual states. Second, the concept of Four-Constitution of Huang Yuan-Yu(黃元御) and Li Ji-Ma(李濟馬) is same. Third, Huang Yuan-Yu(黃元御) doesn't have a standpoint of five-phase on Nei-Ching Medicine, but a standpoint of five-phase on Yi-philosophy. Fourth, water, fire, metal, wood is Four-Constitution that middle qi transformed. Fifth, the middle qi is yang-earth and yin-earth of the spleen and stomach, the physiological function of four viscera is maintained by the movement of ascending and descending of yin and yang earth. Sixth, The middle qi is main role of Four-Constitution. Exchanging of water and fire and the movement of ascending and descending of metal and wood depends on the earth. Seventh, generally medicine researchers speak that human mind is a main role of psycho-function of heart, but Huang Yuan-Yu has the standpoint of spleen-stomach oriented seven emotions not human-mind oriented viewpoint. It represents that a existing thinking of heart-earth center is changed to medical viewpoint of spleen-earth center. Eighth, There is enough ground for controversy on where is the middle point of human in five viscera. Is that spleen or heart? Huang Yuan-Yu(黃元御) insists that the spleen and stomach is middle point, but the standpoint in Four-Constitution medicine of Li Ji-Ma(李濟馬) is that middle point is heart.