Abstract -- We have constructed a web-based disaster planning and exercise tool using active server page and JavaScript technique. By using the tool, users can construct disaster organizations which comply with the organization of Incident command system. Besides, users can play their roles via the INTERNET about the reaction that they should do during the disaster response. The tools have been tested in 2 virtual drills about hospital disaster response. Forty-seven persons were joined these 2 drills. About 80 percent of users granted that the system could help them to familiarize the disaster response contents and procedures. In a subjective survey about improving the knowledge of disaster response, 87 percents of users got improved. Disaster planning via the INTERNET and virtual exercise tools can help disaster training.