Abstract: Corrosion fracture of the substation grounding grid leads to a decrease in grounding performance, which is prone to electric accidents caused by grounding short circuit. The substation grounding grid is affected by the running time, the number of lightning strikes and the chemical composition of the soil. The corrosion breaking speed and degree are different. The traditional sampling detection method works. Large amount, incomplete detection, low detection rate, long interval between detection cycles, and major safety hazards. The prior art means is limited by the distribution of the grounding down conductor, and it is difficult to perform complete measurement and diagnosis of the entire grounding grid. Therefore, an effective fast and non-destructive detection method is urgently needed to realize the diagnosis of the grounding network defect. In view of the above situation, this paper introduces electromagnetic wave detection technology, which is applied to the diagnosis of grounding grid breakpoints, builds a simulation test platform, and tests the grounding conductor breakpoint test to verify the feasibility of electromagnetic wave detection technology in the diagnosis of grounding grid breakpoints. Explore new technologies and methods for grid operation and maintenance.