Due to a global energy problem, there is a rising interest in energy saving around the world, and the lighting energy used in buildings accounts for 22% to 28% of total energy used in buildings. Therefore, reducing the consumption of lighting energy could bring effective energy saving. The purpose of this study is to suggest the light shelf system according to the distance with the skylight that could reduce lighting energy consumption. The system suggested in this study is the system that improves the unfamiliarity of simple fixed light shelf while reducing lighting energy consumption by applying different width and angle of light shelf as well as a different distance between the light shelf and the skylight. It is possible to evaluate the energy performance for each season through the full-size test-bed that could realize actual housing conditions for 24 hours a day, 365 days a year to find an appropriate value so that indoor daylight distribution can be confirmed and the consumption of lighting energy used in indoors can be reduced. The light shelf system suggested in this study can be used as the basic design data for various design elements in a building.