The purpose of this study was to test the effectiveness of the light-shelf system combined with IT to save lighting energy in resident space. According to the multiple variables that affected intensity of illumination, various experiments were designed and conducted. The main findings of this study were following: (1)the optimal level of light-shelf system was formulated which met the appropriate range of intensity of illumination in living-room; (2)although the mixed light-shelf system indicated a high performance, it could often provide discomforts to residents according to the degree of exposure; (3)artificial lights using light-shelf system combined with IT showed a higher effectiveness than those using fixed light-shelf system displayed. This study provided initial information of light-shelf system formative processes that could contribute to the lighting energy diminution. Future studies should focus more on multiple approaches regarding different types of resident space planning.