The concept of Myeongmun(命門) could be found in early medical texts such as "Naegyeong (內經)" and "Nan-gyeong(難經)", but the real idea about Myeongmun(命門) had mainly originated from "Nan-gyeong", in successive medical research. The concept of Myeongmun in "Nan-gyeong" could be read as an organ without form, and under the influence of Taoism theory, the concept of Myeongmun could also be understood as Danjeon(丹田). The theory about Danjeon in Taoism theory affected the concept of Myeongmun in medical theory to be closely related with the concept of Hwa(火), especially Sanghwa(相火). Through the theoretical development of Myeongmun and Sanghwa, the concept of Sanghwa could have been understood as a kind of Hwa(火) in human body, and the theoretical development like this had appeared from the time of Geumwon(金元) dynasty, when many medical doctors had experienced the Naedan(內丹) theory of Taoism. Under the influence of Taoism theory, from the time of the Geumwon dynasty to Myeong(明) dynasty, efforts to explain the concept of Myeongmun and Sanghwa in the human body made various meaningful theoretical products, which was not well-known within medical theories of ancient times. We need to recognize the differences in the understanding of the concept of Myeongmun and Sanghwa among each medical doctors, especially among those that showed opposite views. This study is based on the opinion that the difference in the understanding of the concept of Myeongmun and Sang-hwa among each medical doctors had been mainly due to the difference of understanding and analyzing the Taoism theory as the origin of the Myeongmun and Sanghwa theory in medicine. Regarding this, this study will take an overview of the successive development of Myeongmun and Sang-hwa theory in medicine, and will also look into the concept of Danjeon and Sanghwa in Taoism theory, which will allow better understanding of the progress of development of the Myeongmun and Sanghwa theory.