Recent researches have shown that gut microbiota play an important role in pathogenesis of immune-related disorders.Type 1 diabetes mellitus,as an autoimmune disease,has received increasing attention,especially in terms of the relationship between the pathogenesis and intestinal microbiota.Change of gut microbiota is an important risk factor of the pathogenesis of type 1 diabetes mellitus which have been confirmed with the animal model studies.This article reviews the role of gut microbiota in the pathogenesis of type 1 diabetes mellitus,and the influence of gut microbiota on host immune response for possible prevention and treatment of type 1 diabetes mellitus in the future.