Abstract：TANG Rongchuan，a Qing Dynasty physician，expounded the intrinsic connection between medicine and Zhou Yi（The Book of Changes）in his treatise Yi Yi Tong Shuo（Comprehensive Discourse on Medicine and the Yi）. This work embodies profound doctrine of interconnection between medicine and Zhou Yi，primarily manifested through physiological and disease perspectives. The physiological framework employs the ideas of Liangyi（Two Polarities），He⁃ tu（River Chart），and Bagua（Eight Trigrams）in Zhou Yi to interpret yin-yang theory，fetal development，female sev⁃ en/male eight physiological cycles，and visceral manifestation theory. The disease perspective utilizes Renshen Bagua （Eight Trigrams of the human body），Jiaoyi（Exchange），Hugua（Interlocking Hexagrams），Zagua（Miscellaneous Hexagrams）， Liugua（Six Hexagrams）， Bianyi（Transformation）， Yaowei（Line Positions）， and Bagua Fangwei （Trigrams' Directions）to elucidate therapeutic principles， formula design， and medicinal efficacy. TANG Rongch⁃ uan's doctrine represents the maturation of ancient Chinese doctrine of interconnection between medicine and Zhou Yi， establishing novel paradigms for exploring relationships between traditional Chinese medicine and Zhou Yi.