For a disaster whose scale includes an urban area, it is difficult to be studied with physical experiments. Numerical simulation is found a very efficient tool for such problem. This paper aims at developing an integrated urban earthquake simulation system (UESS) that uses GIS as the model source, CAD as the model generating tools, FEA as damage prediction, and virtual reality (VR) as the post-process platform. An automatic procedure was developed to buildup the 3D structural model of buildings in an urban area, as well as to simulate their earthquake performances, from the digital map of GIS. And the simulation results were presented in an integrated interface with a GIS view-port for position finding, a CAD view-port for 3D structural damage identification, and a VR view-port for 3D dynamic structural vibration display. An urban example with more than 7000 buildings was select to demonstrate the feasibility of proposed system. For a disaster whose scale includes an urban area, it is difficult to be studied with physical experiments. Numerical simulation is found a very efficient tool for such problems. This paper aims at developing an integrated urban earthquake simulation system (UESS) that uses GIS as the model source, CAD as the model generating tools, FEA as damage prediction, and virtual reality (VR) as the post-process platform. An automatic procedure was developed to buildup the 3D structural model of buildings in an urban area, as well as And the simulation results were presented in an integrated interface with a GIS view-port for position finding, a CAD view-port for 3D structural damage identification, and a VR view-port for 3D dynamic structural vibration display. An urban example with more than 7000 buildings was select to demonstrate the feasibility of proposed system.