Abstract： Atopic dermatitis is a common allergic skin disease. In Chinese medicine， it is believed that its pathogenesis is closely related to the theory of "spleen governing defense qi". The spleen regulates the defense qi to protect the body externally and transforms nutrients internally to nourish the five viscera；the intestinal flora can serve as the modern medical basis for the "spleen governing defense qi" theory and is closely related to the pathogenesis of atopic dermatitis. This relationship is mainly reflected in aspects such as immune response，intestinal barrier，and intestineskin axis. "Spleen governing defense qi" is a refined and elevated concept of the spleen's physiological functions and its role in defending against pathogens. The functions of intestinal flora have certain similarities with the "spleen governing defense qi". When spleen and stomach functions are impaired， external pathogens can easily cause alteration of intestinal flora，thereby affecting the prognosis of atopic dermatitis patients. This article explores the action mechanism of intestinal flora in the occurrence and development of atopic dermatitis based on the "spleen governing defense qi" theory，aiming to provide insights for acupuncture treating atopic dermatitis.