The grounding resistance of the high-voltage tower is generally formed by welding a galvanized sheet into a grounding grid. The corrosion resistance of the galvanized sheet is gradually increased by the corrosion of the soil. The resistance of the grounding resistance directly affects the lightning-leading effect, in order to grasp the transmission system during the rainy season. The grounding resistance of high-voltage towers prevents the grounding resistance from exceeding the standard and causes lightning damage to the transmission line. A new type of high-voltage tower grounding resistance online monitoring system is researched and designed. The monitoring system includes online monitoring device and background data management system. The monitoring device uses the dual magnetic circuit method to measure the grounding resistance of the high voltage tower, and wirelessly transmits the measured grounding resistance data to the background data management system. The background data management system can draw the curve of the grounding resistance of each tower with time and form The data report can know the change of the grounding resistance of each tower in real time. The actual use of the system has obvious effect on finding the high-resistance grounding resistance in time, which is of great significance for ensuring the power supply safety of the transmission line.