Spacer is an important component of GIS and play a very important role in their safe and stable operation.They are mainly manifested in mechanical fixation and electrical insulation. Air-tight insulators also play a role inseparating air chambers. In order to study the inherent modal characteristics of basin insulators under different volt-age levels

this article establish a finite element model of basin type insulators with five voltage levels of 110

220

330

550 k V

and 750 k V. The five voltage levels are simulated by simulation 7 th-16 th mode shapes and natural fre-quencies of basin insulators. The simulation results show that the intrinsic mode characteristics of the basin insula-tors under different voltage levels have certain commonalities

and they have more commonalities in the double rootmode

but more differences in the non-double root mode. The research in this paper provides guidance for detectingthe surface state of pot insulators by vibration method.