Abstract: This paper mainly introduces the application of X-ray detection technology in GIS equipment defect diagnosis, and introduces three cases of X-ray detection technology in GIS fault diagnosis. This paper mainly introduces the application of X-ray detection of GIS internal structure assembly, the looseness and damage of components, and introduces the effect of X-ray on PRDP map and the application of medical CT3D imaging analysis. Finally, from the three aspects of the feasibility, effectiveness and safety of X - ray detection technology are summarized, and the main achievements and suggestions of X-ray detection technology in GIS equipment defect diagnosis are expounded.