Concealed steel wire ring theft-proof nut

The utility model relates to a concealed steel wire ring theft-proof nut, which is a non-detachable theft-proof nut of a connector. The concealed steel wire ring theft-proof nut is provided with a nut body, and is characterized in that the inner hole of the nut body is provided with a concentrically conical ring groove, wherein, the small end of the concentrically conical ring groove is positioned on the screw in end of the nut. The inner part of the conical ring groove is provided with an elastic open type steel wire ring which can be screwed on the screw threads of a bolt. When the nut is screwed reversely, the small end of the conical ring groove acts on the steel wire ring and causes the diameter of the steel wire ring to be shortened to tightly press on the screw threads of the bolt; thus, the nut is effectively prevented from being detached when screwed reversely, and the theft-proof purpose is realized. The utility model has strong anti-detaching capability, and can replace the existing theft-proof nuts in use.