Light is one of the comfort factors in the environment, which unwittingly has a direct impact on the human beings. An environment without natural light can gradually cause illness. Light energy accounts for 25% of energy consumption, therefor it has a main rank in studies. As Shiraz is a southern city with considerable sunny days in a year, illuminance of this source can be studied more exactly equipment and convenient ways can be recognized in order to reach efficient use. First of all, the documents analyzed in an analytical-describtive method. Then, the studied issue had been observed in a sample place, and analyzed by the simulation. At last, a type of light guidance system had been used in order to offer the efficient light.Vertical light pipe has been analyzed, in order to provide the quality and quantity of office illuminance in medium depth plan building. Analysis Autodesk Ecotect 2010 version had been used for modeling and Radiance Control Panel for light analyze. The simulation results of the determined office room, had shown some issues such as, light dazzlement, light concentration and light reduction in the different hours of a day of the special months in a year. The findings suggest that, it’s possible to use sunlight for sufficient illumination by using DGS , such as a lightpipes if daylighting process would be revised in the glare and illumination distribution in the different times. It also, offers that the light pipes can be used in the other types of buildings.