AIM:To observe the effect of later laser photocoagulation for the treatment of the branch retinal vein occlusion (BRVO) at the early and late stage. METHODS:Totally 125 cases (125 eyes) with BRVO were divided into two groups:a early therapeutic group of 68 cases (68 eyes) and a later therapeutic group of 57 cases (57 eyes). Visual acuity, intraocular pressure (IOP), fundus fluorescein angiography (FFA) and optical coherence tomography (OCT) were recorded before therapy. The early therapeutic group was treated with krypton laser photocoagulation at baseline: krypton red laser was applied to obvious hemorrhage areas, krypton yellow laser was applied to obvious macular edema, krypton green laser was applied to the rest,retrobulbar TA at the dose of 40 mg was injected after laser photocoagulation. The later therapeutic group was treated with peroral drugs such as jolethin, vitaminC, calcium dobesilate in 1-3 months, retrobulbar TA at the dose of 40mg was injected in obvious macular edema. According to the capillary nonperfusion area showed by OCT and FFA at follow-up visits, the laser photocoagulation was applied.The follow-up was 1 year. RESULTS:In early therapeutic group of 68 eyes, visual acuity was improved in 49 eyes(72.1%), stable in 16 eyes(23.5%), and decreased in 3 eyes(4.4%). In later therapeutic group of 57 eyes, visual acuity was improved in 35 eyes(61.4%), stable in 8 eyes(14.0%), and decreased in 14 eyes(24.6%). The course of reduction or elimination of macular edema of early therapeutic group was significantly shorter than that of later therapeutic group, the rate of cystoid macular degeneration and macular hole were pretty reduced, the course of absorption of retinal hemorrhage of early therapeutic group was shorter than that of control group. No eye of cystoid macular degentation, macular hole or vitreal hemorrhage was noted in early therapeutic group,but 14 eyes occurred cystoid macular degeneration or macular hold, 9 eyes of vitreal hemorrhage caused decrease of visual acuity in later therapeutic group. CONCLUSION:The treating efficacy of early laser photocoagulation for the treatment of the BRVO was better than that of later laser photocoagulation,as it can maintain the visual functions uttermostly.Laser photocoagulation can promote the absorption of retinal hemorrhage, reduction or elimination of macular edema, prevention of cystoid macular degeneration, prevention of retinal neovascularization and vitreal hemorrhage. No adverse events following early laser photocoagulation treatment were observed.