Our country has a convoluted coastline and the marine weather fluctuates locally, so it needs effective AtoN operation for the safe navigation of vessels and fishing boats sailing the coast. Especially, large beacon must ensure the safety of the vessels and always lit at night. If large beacons installed in the lighthouse are not lit, vessels can not assure their location. Thus the accidents is likely to occur, which can cause great economic damage. In this paper, we developed a monitoring system of large beacon to monitor and control the status of information. This system was designed for a special purpose of taking precautions against possible accidents on the sea.