The utility model discloses an online warning board of overhead power line belongs to circuit auxiliary device technical field, including the warning board space of a whole page, be equipped with the warning board frame on the warning board space of a whole page, warning board background and warning poster, the warning board frame lies in the outside of the warning board space of a whole page for the rectangle, the warning poster is located the inboard of warning board frame, the part of warning board background for detaching warning poster and warning board frame on the warning board space of a whole page, the tow sides of the warning board space of a whole page have the same above -mentioned structure, both ends all are connected with suspension clamp about warning board space of a whole page top, the outside of wire is equipped with preformed armor rods, the preformed armor rods parcel is in the outside of wire, suspension clamp's upper end and preformed armor rods pass through bolt immobilization connection, the tow sides of the warning board space of a whole page all are equipped with high intensity level reflective membrane, this device is not influenced by in wire forceful electric power magnetic field, safety and environmental protection, therefore, the carrier wave prepaid electric energy meter is low in cost, continuously play the warning effect, can effectively reduce operation under the line, it rates to reduce external damage, improve circuit safe operation level.