Abstract:In 126kV gas insulated switchgear (GIS), a bus plays an important role in the collection, transmission and distribution of electric energy. Single-type axial bellows are widely used in 126kV GIS equipment of various GIS manufacturers. Regarding the application of single-type axial bellows in 126kV GIS project, the basic functions, setting principles, tie rod setting, fixing support setting, nut setting inside and outside bellows, and multi-bellows coordination of single-type axial bellows are discussed and studied in this paper in order to avoid the defects of 126kV GIS products caused by improper use of the bellows.