Abstract: The Major Principles of the Five Elements is a collection of Yin-Yang and Five Elements theories in the middle ancient period of China. The Xiangshu model of Yin-Yang and Five Elements is the basic paradigm to clarify the world and its existence. "Constitution" and "Function" are a pair of important categories used in ancient philosophy to describe the relationship between the nature and function of ontology. Based on the two temporal and spatial rhythms of the Heluo Heaven and Earth Five Elements view and the Jiugong Bafeng spatiotemporal view constructed by the Xiangshu model, The Major Principles of the Five Elements explains the connotation and characteristics of traditional medical constitution and function, aiming to elucidate the evolution process of the pathogenesis of constitution and function, guide the dialectical thinking of constitution and function, and flexibly select and combine drug properties and flavors to harmonize the human constitution and function. This paper provides a unique perspective and method for explaining the concept and connotation of constitution and function in traditional Chinese medicine by glimpsing the gradual changing way of thinking in traditional medicine from the Pre-Qin period to the Tang Dynasty.