Virtual reality-based virtual emergency drill has wide application. But existing drill systems lack accurate environmental simulation and plan support. In this paper, a virtual emergency drill simulation system (VEDSimu) was proposed. It solved the entity message passing problem and large-scale simulation model computing problem. Then, a virtual emergency drill system (VEDSys) was constructed. It implemented plan script system, plan inference engine, evaluation system and virtual reality client based on VEDSimu. Furthermore, VEDSys was proved to be feasible, efficient, and scalable with the application in actual company virtual fire drill.