Atopic dermatitis(AD) is a common chronic，recurrent and pruritus inflammatory skin disease in dermatology.The author believes that the core pathogenesis of AD lies in the lack of innate endowment and the acquired disorders of viscera，especially the disorder of spleen and stomach.According to the different age groups and stage of the disease，the core pathogenesis has dynamic variability.AD in infancy and childhood is located in the heart，and related to the spleen and kidney.In the acute stage，it is mainly characterized by hyperactivity of heart fire.The subacute stage of AD is mainly characterized by intermingling of heart fire and spleen deficiency.The chronic and stable phases of AD are mostly manifested as yin deficiency and blood dryness due to impairment of yin by excessive heat，blood deficiency and blood dryness，or spleen and kidney deficiency caused by impairment of prolonged illness.In adolescents and adults，AD is located in the spleen，which is closely related to the liver and kidney.In the acute stage，the pathogenesis of AD is mainly dampness and heat in liver channel，and blood heat producing wind.In chronic phase，spleen deficiency and dampness accumulation，dryness and dampness intermingled.In the stable stage，spleen deficiency and blood dryness，yin deficiency and blood dryness，or spleen and kidney deficiency.In the elderly，AD is located in the kidney and closely related to the spleen.The pathogenesis of AD in the acute phase is mostly stubborn wet accumulation in skin，while in the chronic and stable phases，it is mostly spleen and kidney deficiency.The grasp of thinking of treatment based on syndrome differentiation should start from the following points：paying attention to the innate kidney essence，strengthening the regulation of endowment，guarding the acquired spleen and stomach，nourishing the five viscera，treatment based on syndrome differentiation from multiple perspectives including age，stage，deficiency and excess，and treating both manifestation and root cause of disease，paying attention to prevention and care，both internally and externally，and paying attention to the whole.It is of great significance for guiding the clinical diagnosis and treatment of AD by adopting a variety of treatment methods of traditional Chinese medicine，regulating endowment，treatment based on syndrome differentiation，and giving full play to the advantages of traditional Chinese medicine.