Three-phase voltage-withstanding tool

The invention belongs to the field of electrical performance testing devices, and particularly relates to a three-phase voltage-withstanding tool. In order to solve the technical problem that a withstand voltage test device in the prior art does not provide shielding measures for a connecting conductor, so that the withstand voltage test device cannot be suitable for a withstand voltage test of a higher voltage class, the invention provides a three-phase withstand voltage tool which comprises a shell and an insulating sleeve connected to the shell, three test interfaces used for being connected with a bus cylinder are arranged on the shell, a connecting conductor which is electrically connected with the pressurizing conductor in the insulating sleeve and used for being electrically connected with three phases of a bus at the same time is arranged in the shell, and shielding structures used for shielding electric fields at the ends of the connecting conductor are arranged at the two ends, in the axial directio