Abstract: In this paper, from the contact electric field or magnetic field measurement method and the non-contact transient electromagnetic method, the development of electromagnetic field detection technology in the diagnosis of grounding network defects is summarized. From the principle of electromagnetic field detection technology, the defect diagnosis is respectively made. Methods and experimental research are reviewed in recent years. The important research results of electromagnetic field detection technology in the field of grounding network defect diagnosis are reviewed. Based on the above review, the research direction of electromagnetic field detection technology in grounding network defect diagnosis is prospected. Provide reference for the development of grounding grid diagnostic electromagnetic field detection technology.