The utility model provides an inductance seal structure and 250kV high tension cable oscillating wave partial discharge test system. This inductance seal structure, including the inductance core, connect respectively in the first insulation apron and the 2nd insulation cover plate at inductance core both ends, the cover is located insulation cylinder body on the inductance core, the insulation cylinder body both ends connect respectively in on first insulation apron and the 2nd insulation cover plate, and connect in a plurality of insulating screw rod connection structure between first insulation apron and the 2nd insulation cover plate, insulating screw rod connection structure encloses and locates around the inductance core and lie in in the insulation cylinder body. The utility model provides a technical scheme, sealed humidity resistance is good, still can reduce inductance volume and weight, and the difficult air gap that produces is good with the laminating degree of other equipment, can not result in partial discharge and corona phenomenon.