Common variable immunodeficiency (CVID) is the most common primary immunodeficiency that is characterized by low immunoglobulin levels in the body. CVID is indicated by failure of b cell differentiation and decrease production of immunoglobulins such as IgG and at least one of IgA or IgM. CVID patients with enteropathy (E-CVID) show a decline in already low levels of intestinal IgA that distinguishes from other CVID patients. Previous studies from our lab showed that absence of IgA in the small intestine determine the factor of CVID enteropathy. We also found that microbiota is important for the development of E-CVID. Due to the importance of the gut microbiota in the E-CVID, it is important to establish an animal model which is not only genetically similar to E-CVID patients but also similar in terms of microbiota. We have established a humanized microbiota mouse (HMM) model to investigate phenotypic traits, cellular and molecular features, and characteristics of E-CVID patients in HMM. Results showed similar phenotypic traits, gene expression and intestinal immunity and lymphocyte population in HMM and in E-CVID patients. HMM model has potential application of understanding the mechanism and function of host to microbe interaction.