Abstract: Aiming at the problems of large volume and cumbersome installation of the terminal grounding device during the factory insulation test of the fracture of 550kV Gas Insulated Switchgear (GIS), a miniaturized grounding switch-type adaptive tooling design scheme is proposed. By optimizing the structure of the conductive loop, improving the shielding design of the static contact, and verifying the rationality of the electric field distribution of the tooling through COMSOL simulation analysis, the miniaturization and lightweight of the tooling are realized. This design provides an efficient and convenient grounding solution for the withstand voltage test of 550kV GIS fractures, and has important engineering application value.