The complement system is a protein response system with a precise regulatory mechanism, which has the functions of mediating inflammation, regulating immune response, dissolving cells and clearing immune complexes. Diabetic retinopathy(DR)is a common and severe ocular complication of diabetes and one of the common irreversible blinding eye diseases in ophthalmology, and its pathogenesis is complex, including hypoxia, oxidative stress, inflammation and abnormal polyol metabolism pathway. In recent years, there has been more and more evidence that dysregulation and inflammation of immune system are important factors in the pathogenesis of DR, and a variety of complement proteins play an important role in key processes such as inflammation regulation and angiogenesis. Therefore, the central purpose of this review is to discuss the role of the complement system and related regulatory proteins in DR, with the aim of elucidating the close relationship between the complement proteins and the occurrence and development of DR, and providing important references and new ideas for the prevention and treatment of DR. At the same time, the clinical research of complement system-targeted drugs is further elaborated.