Terahertz(THz)technology,as an emerging tool for characterizing biomacromolecules,has rapidly developed over the past few decades,demonstrating significant application potential in multiple fields.Defensive qi is a vital energy in the human body,responsible for defense functions by warming the skin,regulating the opening and closing of the striae and interstices,and resisting the invasion of external pathogens.Defensive qi is one of the core concepts for disease prevention and health maintenance in traditional Chinese medicine(TCM).However,due to the high abstraction and complexity of TCM theory,the scientific connotation and mechanism of action of defensive qi remained incompletely elucidated.THz waves have the unique physical properties of molecular vibration sensitivity,penetrability,and thermal radiation effects,and are highly sensitive to biological tissues,which make THz technology a promising tool for defensive qi research.By analyzing the characteristics of THz waves,this paper explores the feasibility of applying THz technology to investigate the circulation patterns of defensive qi,the prevention and treatment of disorders related defensive qi,the pathological essence of defensive qi diseases,the material basis of defensive qi,the screening of defensive qi disorders,and the development of novel drugs targeting defensive qi disorders.This approach provides a new perspective and methodology for the research of TCM fundamental theory.