Diabetic retinopathy(DR)is the most common microvascular complication of patients with diabetes mellitus, and it has become one of the leading causes of visual impairment among working-age people worldwide. The pathogenesis of DR is complicated with multiple mechanisms. Plenty of studies have indicated that circadian rhythm and clock genes are closely related to the pathogenesis of DR. Circadian rhythm is a physiological process regulated by clock genes, which takes 24h as a cycle and is consistent with the changes of light and dark outside. Circadian rhythm regulates various physiological activities of the body. The disturbance of circadian rhythm induces DR by affecting the blood glucose level and the physiological homeostasis of the eye in patients with diabetes mellitus, and clock genes may be involved in the pathogenesis of DR by regulating oxidative stress response, inflammatory response, retinal autophagy rhythm, mitochondrial dysfunction and endothelial progenitor cell function. This paper will introduce the generation and regulation mechanism of circadian rhythm, as well as the internal circadian rhythm of retina, and further discuss the influence of circadian rhythm and clock genes on the occurrence and development of DR, aiming to provide a reference for the prevention and treatment of DR.