This paper proposes the fundamental design and analysis approach on energy conservation of green buildings using a natural daylight strategy. The proposed energyconservation scheme on power energy utilization of green buildings has been an important research topic in recent years due to the increasing price of international petroleum. Most of the power losses in typical buildings are from lights, motor loads, and air conditioners. This paper presents the design scheme on light management system to reduce power consumption of the power system in a research building by means of the utilization of natural daylight. Based on available illumination, the required supplementary artificial lighting is calculated and evaluated to meet the given lighting requirements.