Recently, buildings take up 39% of total energy consumption in Korea, 28% of which is consumed as lighting energy. Therefore, various studies are conducted in order to reduce indoor artificial lighting energy consumption. Natural lighting systems can efficiently save lighting energy, among which the light shelf is a system with excellent lighting performance and economic feasibility using the inflow of natural lights. The performance of light shelves is determined by the form of reflector in terms of reflection, and rays that apply curvature are excellent due to the diffusion of light. Therefore, this study focused on testing the performance of light shelf applying curvature, and conducted seasonal research using a real-scale test bed for the lighting performance of light shelf applying curvature that can be implemented round-the-clock and year-round. Moreover, this study aimed to verify the energy saving efficiency by applying change by the curvature value of light shelf reflector based on the width of light shelf and the meridian altitude of the sun. Keyword: Light-Shelf System, Curvature, performance evaluation