Abstract: As the most common primary glomerular disease in the world, IgA nephropathy (IgAN) is one of the major causes of end-stage renal disease (ESRD). With the in-depth studies of IgAN, researchers have gradually clarified the important roles of galactose-deficient IgA1 (Gd-IgA1) production, gut microbiome dysbacteriosis, genetic susceptibility and immune system abnormalities in the pathogenesis of IgAN. Therefore this review summarized the latest researches based upon the four-hit hypothesis of IgAN, dysbacteriosis, genetics and immunological mechanism and provides comprehensive perspectives for understanding the multidimensional factors of this disease.