Abstract: Provided is a disaster warning system with active geofencing, which includes: an information collection unit for collecting real-time disaster information, real-time weather information and document information on existing disasters; a geofencing analysis unit for complexly analyzing the information to classify the scope of an area that causes a disaster damage after the disaster into caution and danger zones on a map based on geofencing, disaster situations and time series; an information generation unit for generating content for indicating the caution and danger zones on the map; and an information notification unit that provides the received content to a user mobile phone in a section set by a disaster damage prediction range, to allow the user mobile phone to indicate the caution and danger zones on the map.