The final goal of this research is to develop a facade system with a sun-shading device that is autonomously controlled as an integrated solution for daylight and electric lighting. The facade system has photovoltaic sensors (PV-slats) on the outer surface of the sun-shading device and can monitor daylight illuminance by using output of the photovoltaic sensors. This research work aims to propose an appropriate sun-shading control strategy for the facade system with PV-slats. It proposes a method to obtain monthly thresholds of vertical global illuminance on windows, as functions of solar altitude or solar profile angle, to judge whether the windows receive direct sunlight or not. It also proposes a sun-shading angle named PV-slat angle. The proposed system includes electric lighting that supplements insufficient illuminance in rooms. Compared with the basic sun-shading control angle, PV-slat angle showed better results in both air-conditioning load and lighting simulations.