This study deals with the evaluation of the electrical lighting energy saving from daylight in a new educational building via EnergyPlus building simulation software. It describes the background of daylight availability for potential energy saving, daylight-linked control and energy saving prediction. The DElight module in EnergyPlus is used to calculate the lighting energy saving based on the daylight availability. Computational simulation performs for a selected single zone as well as for the whole building. This report has evaluated the role of influential factors on lighting energy saving. It concludes that the annual potential energy saving could be up to 49.98% of lighting electricity consumption and between 73.91% to 40.98% among different rooms in the building. A discussion is also given about comparison with another study for the same building using other methods. This report implies the potential of daylight integration in building design to achieve sustainable development in the building sector.