Double-skin facade (DSF) is getting more and more popular these days due to its energy-saving potential and aesthetics. This particularity design brings certain difficulties to the fire protection of the building. Especially for natural-ventilated DSFs, the smoke flow between floors and DSF is more complicated depending on ventilation strategies. In order to gain more understanding and to acquire reliable data for future design, a naturally ventilated DSF building, Center of Sustainable Energy Technologies in Ningbo, was studied numerically. Computational fluid dynamic (CFD) analysis was carried out focusing on the characteristics of smoke distribution. Results showed that even though CSET building met the national fire safety requirement, it still failed to prevent fire spreading or ensure evacuation safety of occupancy. Simulations also suggested that opening up the DSF during fire would actually be more effective at preventing fire from spreading as well as ensuring occupancy evacuation.