“Skin is one of the five body concepts in traditional Chinese medicine theory, and its connotation exists in various understandings and expressions in the Yellow Emperor's Inner Canon, involving tissue structures such as hair follicles, pores, and floating collaterals, reflecting different medical practices' understanding of skin. The function of skin is also reflected by its subsidiary structures. With the development of the theory of meridians and organs, the skin, as a body tissue, has integrated with it and formed various modes of attachment. The skin and hair are nourished by the blood and qi of the body, which is also an external manifestation of the balance of blood and qi. As the lungs have the function of regulating qi and regulating respiration, they are the driving force behind the circulation of blood and qi, forming the related understanding of "the lungs governing the skin and hair"; The "Sun Main Table" originates from the fusion of meridian theory with skin, flesh, and bone, and is a product of the early combination of body shape differentiation and meridian differentiation for exogenous fever; The concept of 'the heart on the surface' is closely related to early blood letting therapy. The floating blood vessels on the surface of the body are an extension of the heart's main blood vessels. Blood letting therapy can play an important role in promoting blood circulation, purging heart fire, and regulating the mind and spirit. This study explores the conceptual connotation of skin and the construction process of related theories, in order to fill the gaps in current understanding of skin theory and promote the enrichment and improvement of the body shape theory in the Yellow Emperor's Inner Canon.”