Ethnopharmacological relevance: Astragali Radix (AR, Huangqi in Chinese), the dried root of Astragalus membranaceus (Fisch.) Bge. var. mongholicus (Bge.) Hsiao or A. membranaceus (Fisch.) Bge., possesses diverse therapeutic effects against fatigue, dyspepsia, diarrhea, heart diseases, hepatitis, and anemia. In recent years, increasing evidence has indicated the multiple immunomodulatory activities of AR in preclinical and clinical studies. Aim of the review: This review attempts to elaborate the immunomodulatory effects of AR and its potential application in the treatment of immune related diseases. Materials and methods: A comprehensive literature search AR was carried out using multiple internationally recognized databases (including Web of Science, Google Scholar, PubMed, ScienceDirect, Wiley, ACS, Springer, Taylor & Francis, and CNKI). Results: The immunomodulatory effects of AR are closely attributed to its active constituents such as polysaccharides, saponins, and flavonoids. We also demonstrate that AR can be used as a potential therapeutic intervention for immune related diseases through regulating immune organs, mucosal immune, and immune system (innate immunity and acquired immunity). Conclusion: AR promotes the development of immune organs, enhances mucosal immune function, increases the quantity and phagocytic capacity of innate immunity, promotes the maturation and differentiation of acquired immunity cells, and improves the expression of antibodies in acquired immunity. We believe that AR has a broad research space in the adjuvant treatment of immune related diseases, which could be a breakthrough point to improve the application value of AR.