Diabetic retinopathy is one of the complications of diabetes in the eye and one of the major blinding eye diseases. It is well documented that about two-thirds of diabetic patients with onset of diabetes for more than 15 years suffer from diabetic retinopathy. Diabetic retinopathy produces neovascularization as a result of acute hypoxic stimulation of large areas of tissue caused by retinal nonperfusion. Neovascularization begins with endothelial proliferation buds of intraretinal vessels and grows in the potential gap between the vitreous and retina. Neovascularization is fragile and prone to retinal and preretinal hemorrhage, and when there is hemorrhage in the retina and vitreous hemorrhage in large amounts or repeatedly, it often cannot be absorbed in its entirety and produces mechanized film that attaches to the retinal surface, and contraction of such mechanized material can form retinal detachment and cause blindness. Fundus fluorescence angiography, in a certain sense, can reflect the severity of retinal lesions, it can show the non-perfused areas of the retina and neovascularization, which can provide the basis for laser treatment. Blood glucose control has a great relationship with the occurrence, progression and visual prognosis of diabetic retinopathy. If blood glucose control is poor for a long time, not only the incidence of diabetic retinopathy increases, but also the number of people who develop proliferative forms increases. Therefore, once diabetes is detected, lifelong attention should be paid to controlling blood glucose to reach the target value. If proliferative lesions have developed, even controlling blood glucose may not stop the deterioration of the disease. The best time to treat diabetic fundus hemorrhage is before the patient develops conscious symptoms, i.e., before vision loss. The photothermal biological effect of the laser is used to coagulate the tissues of the retina. It does not aim to stop bleeding directly, but indirectly by improving the oxygen supply to the inner retina and promoting the absorption of intraretinal hemorrhage through photocoagulation of the cells in the outer layer of the hypoxic retina, while reducing or eliminating factors related to neovascular growth secreted by the hypoxic retinal nerve cells and degenerating the neovascularization. Diabetic patients should have their visual acuity and fundus checked regularly, and if proliferative lesions appear, total retinal photocoagulation should be performed immediately to avoid serious blinding complications such as vitreous hemorrhage and tractional retinal detachment. Once vitreous hemorrhage and retinal detachment occur, vitrectomy is required.