Being with the changing of world order in the 20th century, the influence of modern science and technology had gradually been expanded into the developing countries. Concerning with the development of traditional Mongolian medicine, the societal changes, cultural transfigurations, and the scientific policies have brought the new era to the medicine in Inner Mongolia. Mongolian medicine had been integrated with Western medicine and Chinese medicine in the end of last century. The transformation of Mongolian medicine in the 20th century has been made by modern medicinal education system, the institutional development and the starting of medical magazines. There has been a medical pluralism phenomenon which has appeared in Inner Mongolia since the last century. This article will demonstrate the development of the 20th century's Mongolian medicine and point out that that will be the important part of its whole history.