Diabetic retinopathy (DR) is the main cause of blindness in diabetic patients. Early diagnosis and intervention are essential to improve the quality of life of patients with DR. Choroidal vascularity index (CVI) is the ratio of choroidal luminal area to total area, which can reflect the structure and blood flow of the choroid, and has been used to evaluate the choroidal condition in various eye diseases. CVI has shown great potential in the prediction, early intervention, disease assessment, and prognosis of DR. The relationship between CVI and photoreceptors needs more research, and CVI may be used as a predictive indicator of photoreceptor health and visual prognosis. In addition, the study of CVI at different layers of the choroid is limited by the accuracy of stratification and the repeatability of measurement. Artificial intelligence and other technologies may provide solutions for this. In the future, through more comprehensive study and the help of artificial intelligence, the value of CVI will be further enriched, which is of great significance for the elucidation of the pathogenesis of DR and serving the clinic.