Strong earthquakes can cause buildings to collapse, fires, and jammed doors and elevators. In this study we used the Internet of Things to develop a smart earthquake disaster prevention system. The system continuously monitors the real-time earthquake warning data of the Central Weather Bureau (CWB). When real-time seismic data are updated, the system immediately obtains the intensity and location of the earthquake and calculates the intensity and time of arrival at different locations. When the earthquake is judged to be dangerous, the system immediately shuts off the gas supply. When residents are determined to be at home by a human body detector, a sound and light earthquake alarm is immediately activated, and real-time earthquake data are displayed on LINE instant messaging platform, short message service (SMS), and electronic displays. Doors are also automatically opened to prevent them from being stuck. Earthquake information is immediately sent to regional elevator management centers to instruct elevators to stop at the next floor, open the doors, and broadcast information on the upcoming strong earthquake. By developing this system, the latest earthquake warning information from the Central Meteorological Administration can be effectively captured, and necessary evacuation and disaster mitigation measures can minimize deaths and property losses from earthquakes.