The software on simulation of building fire and the software on simulation of structural response due to fire both have good performance in their respective fields, but they are not good at the synchronous simulation between building fire and structural response due to fire. In this paper, the synchronous simulation above is made in the virtual reality system based on Vega. This system is a post-processing platform based on a fire simulation software FDS and a FEM software MSC. MARC. FDS and MARC provide scientific results for synchronous simulation, while this virtual reality system shows these results in a visual and lifelike way. This system reveals the link between building fire and structural fire response. In virtual training, this system can help people judge the structural safety by the situation of building fire.