Fundus laser photocoagulation, commonly referred to as “laser”, is commonly performed with an argon krypton ion laser, which uses the thermal effect to form dense photocoagulation sites on the retina, which can close leaky sites to reduce the chance of retinal edema and vitreous hemorrhage. Photocoagulation can also destroy areas of capillary occlusion to reduce the production of neovascularization. In retinopathies where neovascularization is already present, laser can subside the abnormal neovascularization and prevent its further development, preserving useful visual function and significantly reducing the rate of vision loss. If laser treatment is performed in a timely manner, that is, if it is done before vision is lost, it may preserve or save the patient’s vision. However, it is unlikely that the previous vision will be restored, and some patients will have a slight decrease in vision after treatment, which is normal. This treatment can be likened to “throwing away” some of the peripheral vision and focusing on preserving useful central vision. Laser photocoagulation is an effective and convenient treatment for diabetic retinopathy today. Of course, laser treatment has certain side effects, such as temporary blurred vision and mild vision loss, which usually recover after some time. However, there are a few patients with significant vision loss after laser treatment, which is mostly related to the aggravation of macular edema, neovascular hemorrhage and macular detachment caused by fibrous membrane contraction after laser, and also related to the late treatment. It should be reminded that regular review is necessary even after laser treatment, if the lesion develops further, repeated laser treatment for several times is necessary.