The state of yang deficiency is defined as the pathological phenomenon of yang qi deficiency of the body,which leads to the hypofunction or weakness,low metabolic activity,low body responsiveness,and insufficient yang heat.Modern research proves that the state of yang deficiency and the syndrome of yang deficiency are related to both hypertension and hypotension,showing obvious bidirectionality.By searching papers on abnormal blood pressure due to yang deficiency,we summarized the similarities and differences in disease distribution,etiology and pathogenesis,symptoms and signs,treatment,and physiological and pathological mechanisms between yang-deficiency hypertension and yang-deficiency hypotension in this paper.It provided a theoretical basis for the classification and management of abnormal blood pressure according to constitution,and laid the foundation for further clinical investigation and experimental research.