A micro-seismic monitor for preventing illegal mining belongs to the technical field of seismic monitoring equipment, and is used for immediately recording three-dimensional coordinates of areas mined illegally and accurate time and then sending the information to a monitor station. The technical scheme includes that the micro-seismic monitor comprises a sensor, a data collector, a computer, a transformer and a power source, wherein the power source is connected with the computer, the data collector and the sensor respectively, the sensor is mounted in a tunnel, a signal output end of the sensor is connected with a signal input end of the data collector, and a signal output end of the data collector is connected to a signal input end of the computer. The sensor mounted in the tunnel is used for acquiring illegal mining signals and sending three-dimensional coordinates of areas mined illegally and mining time to the computer via the data collector, so that monitoring staff can control illegal mining situations in time. The micro-seismic monitor can not only prevent illegal mining effectively and protect mine resources and safety but monitor earth pressure disasters within a coverage area of the monitor.