Abstract： Endothelial-to-mesenchymal transition （EndMT） is a core pathological process that induces vascular fibrosis and leads to vascular dysfunction during hypertension. The theory of "yang governs qi-transformation and yin governs substance-formation" is an important theoretical framework in the yin-yang theory of traditional Chinese medicine （TCM），which elucidates the transformation of form and qi in the body. This study focuses on EndMT，the core pathological process in hypertensive vascular injury， and integrates it with the TCM theory of "yang governs qitransformation and yin governs substance-formation" to conduct a correlative interpretation of the pathogenesis from both western medicine and TCM perspectives. By reviewing relevant basic and clinical research evidence from western medicine，it clarifies that stimuli such as hemodynamic abnormalities，inflammation，and oxidative stress can activate signaling pathways including TGF- β and Wnt/β -catenin， induce pathological transformation of endothelial cell phenotype，disrupt the vascular endothelial barrier，and trigger vascular fibrotic remodeling. Moreover，the activation level of EndMT is correlated with the degree of vascular stiffening injury. This study elucidates the physiological connotations of "yang governs qi-transformation and yin governs substance-formation" in maintaining vasomotor function and vascular wall structural stability. From the pathological perspective， it distinguishes that hyperactive qitransformation by yang corresponds to excessive activation of the sympathetic nervous system and the renin-angiotensinaldosterone system （RAAS） as well as aggravated inflammatory responses，serving as the functional pathological basis for initiating EndMT， while insufficient substance-formation by yin corresponds to the imbalance of vascular matrix homeostasis and impaired endothelial cell junction structures， serving as the structural pathological basis driving the sustained progression of EndMT. These two aspects interact with each other，giving rise to the overall pathogenesis of yin deficiency with yang hyperactivity，and phlegm-stasis obstructing the collaterals. Targeting the pathogenesis of yinyang imbalance mentioned above，the therapeutic principles of nourishing yin and enriching blood，and subsiding yang and extinguishing wind are established. This study also summarizes the existing experimental research data on single Chinese herbal medicines with yin-nourishing and yang-subsiding effects as well as their corresponding classic compound formulas，and synthesizes the mechanisms by which these formulas improve vascular endothelial function and inhibit vascular remodeling through regulating EndMT-related signaling pathways.