Abstract: Atopic dermatitis is a chronic and recurrent inflarnmatory skin disease characterized by xerosis,pruritus and eczematoid lesions with increased transepidermal water loss.The morbidity of atopic dermatitis has been increasing,while its nature remains unclear.It is likely that genetic background,environment,dcfcctive skin barrier function and abnormal innate and adaptive immunity are all involved in the pathogenesis of atopic dermatitis.Some recent studies have found many factors that may contribute to the development of atopic dermatitis,including the loss-of-function mutation of filaggrin gene,mutation of ORMDL3gene,dysfunction of dendritic cells,Th9,Th22 and Th17 cells,increased expressions of interleukin-31 and H4 receptor,antimicrobial peptides,ceramide and thymic stromal lymphopoietin.