Diabetic retinopathy (DR) is one of the most common microvascular complications of diabetes. In recent years, with the number of diabetic patients increasing annually, the number of DR patients has also been rising, and it has become one of the major blinding eye diseases worldwide. The pathogenesis of DR has not been fully clarified but includes microvascular lesions and metabolic factors. However, with the continuous exploration of the pathogenesis of DR, immune system disorders and inflammation have also been found to be important pathogenic mechanisms of DR and research on inflammation and immune mechanisms in DR have received increasing attention. This article reviews aspects such as the activation of inflammatory cells, the expression of inflammatory factors, and the complement system and explores the important roles of inflammation and immune mechanisms in the pathogenesis of DR, providing a theoretical basis for a deeper understanding of DR and potential explorations of new therapeutic strategies for DR.