Spatial design greatly influences fire evacuation in buildings. Although existing works have comprehensively assessed building spatial design in terms of building circulation, they overlooked how the building layout and emergency signage system affect occupants’ attention allocation during fire emergencies. Therefore, this paper proposes a framework to investigate the effectiveness of building evacuation impacted by building spatial design by integrating building information model (BIM), fire simulation, and virtual reality (VR) technology. A case study was carried out to evaluate building spatial design in terms of building circulation and emergency signage. The results demonstrated that when the signage sizes were relatively small but the spacing and placement heights were reasonable, participants were able to recognize and follow the guide. However, insufficient continuity caused the participants to waste much effort searching for helpful information on evacuation-irrelevant objects, reducing fire evacuation efficiency. Moreover, the signage placed at a higher position has a positive effect on route choice.