The concept of “Microbe-gut-eye axis” holds that metabolites of the gut microbiota are involved in the pathogenesis of various eye diseases. The composition and diversity of gut microbiota in diabetic retinopathy (DR) patients are significantly different from those in non-DR patients. Metabolites of the gut microbiota such as lipopolysaccharide, short-chain fatty acid, bile acids and branched-chain amino acid aggravate or attenuate the progression of DR by regulating the release of inflammatory cytokines, mitochondrial function, insulin sensitivity, immune response, and autophagy of retinal cells. Therefore, gut microbiota and their metabolites play a role in the occurrence and development of DR through multiple pathways. The participation of gut microbiota may open up a new way to prevent and treat DR in the future.