Abstract: To solve the problems such as substation site staff entering live bay by mistake, lack of safe distance from live equipment, expansion of working range, mis-touch equipment of large machines and tools and the difficulty of field personnel supervision, this paper develops a 3D visual operation monitoring system based on UWB location by using 3D model construction technology of substation, 3D location algorithm of ultra-wideband (Ultra Wideband, UWB) signal ranging based on centroid of intersection, monitoring technology based on electronic security fence operation and so on. The system realized the operation monitoring and alarm functions of field workers and large machines in 3D scene, effectively prevented the occurrence of the above problems, and the system has been successfully applied in 220 kV Tongyi substation, which verified the effectiveness of the system.