Objectives : He Meng-Yao(何夢瑤), a doctor from Qing Dynasty, wrote Yi Bian(醫碥, Fundamentals of Medicine), in which he described many things related to Medical Medicine of divination (醫易). As the content includes a lot of teachings for the posterity, I have studied it. Methods : I have taken from Yi Bian(醫碥) the selections related to Medicine of divination(醫易) and explained them. Results : While accepting the principle of upholding yang and suppressing yin based on the understanding of the Book of Changes(周易) that takes a superior man for yang and a small man for yin, He Meng-Yao(何夢瑤), who thought of both yin and yang as Qi (energy), criticized the contemporary malpractice of uniformly applying the principle. In matching the five viscera to the Eight Trigrams(八卦), he put Qian and Dui Trigram(乾兌) to lung, Kan Trigram(坎卦) to kidney, Zhen and Xun Trigram(震巽) to liver, Li Trigram(離卦) to heart, and Kun and Gen Trigram(坤艮) to spleen, which is reasonable. He didn’t fix the position of the vital gate and called it Fire in water(水中之火), and set great store by the role of Fire from Vital Gate(命門火) by calling it Water begetting tree(水生木) when the fire of the vital gate steams the kidney water and turns it into Qi to send it up to liver. He emphasized Water-ascending and Fire-descending(水升火降), which he said involves all five viscera. He also argued that mind runs on the principle of water-ascending and fire-descending. He thought that Qi and blood both originate from kidney, which I think is a significant suggestion. Conclusions : The criticism on the uniform application of upholding yang and suppressing yin, the combination of the five viscera and the Eight Trigrams(八卦), the belief that the Vital gate(命門) is Fire in water(水中之火), the excellent opinion on water-ascending and fire-descending, and the suggestion that Qi and blood both originate from kidney, as presented by He Meng-Yao(何夢瑤), are all theories that should be reasonably appreciated and further developed by the posterity