Objective To investigate the complications of the Branch Retinal Vein Occlusion. Methods Two hundred and seventy-seven cases (277eyes) of branch retinal vein occlusion (BRVO) have been studied retrospectively from 1995 October to 1999 October Results Most cases of BRVO occured after the age over fifty-five. About 81.85% BRVO affected at supiriotemporally and inferiotemporally. The incidence of the complication of BRVO is closely related to the site of obstrution, the larger branch vein occlusion the higher incidence of the nonperfusion area and neovascularization Conclusion The macular edema occured in the early stage of the BRVO, and most non-perfusion areas were observed between six to twelve months. The neocvscularization always observed after one year later from the vein obstruction. So that the patient have to be followed carefully with a long duration. （Chin J Ocul Fundus Dis,2002,18:17-19）