With the increasingly demands of safe monitoring in safe mining, the new monitoring product was evolved, the new and old product are incompatible, overall a one-off upgrade needs too much investment, without using all the original equipment. Based on this problem, KJ100N safe monitoring system of Linnancang Mine was taken as example, the transformation plan of double optical fiber ethernet ring network based on existed equipment without extra investment was put forward, which made the new and old equipment compatible in a safe monitoring system, the technology with advantages of continuous monitoring in upgrade, saving capital investment and labor.