Abstract: In order to ensure the safe and stable operation of GIS equipment, this paper studies the abnormal heating defects of GIS shell bus. In this paper, the mechanism of circulation generation and the cause of heat generation of the bus bar are first studied, that is, the heat generation of the bus bar is caused by the Joule heat of the circulation generated by electromagnetic induction; secondly, combined with the heating case of 220 kV GIS bus bar in a 500 kV substation, through infrared temperature measurement and clamp current meter measurement, it is analyzed that the reason for the heating of the bus bar is that the circulation on the bus bar is too large, while the cross-sectional area of the bus bar is too small and the current carrying capacity is insufficient. Finally, the treatment measures are put forward: Replacing the bus bar with larger cross-sectional area, adding a three-phase short-circuit shunt structure at the inlet end and increasing the pressure block to reduce the contact resistance.