The utility model provides an isolating device is arranged to generating line for transformer test, its characterized in that: include top insulation fixing plate, upper and lower end connecting rod, swivel nut and bottom insulation fixing plate, all be equipped with triangle splint and board in the middle part of top insulation fixing plate and bottom insulation fixing plate's the back and pass through plastics round pin axle rotation connection, first the screw thread opposite direction of screw thread and lower half of internal thread of swivel nut, rather than corresponding, upper and lower end connecting rod is equipped with the internal thread assorted external screw thread with the swivel nut. This isolating device is arranged to generating line for transformer test, simple structure, low cost, convenient to carry, moreover owing to carrying out transformer high -voltage testing during operation, crimping head that the generating line that can demolish was arranged is kept apart with the sleeve pipe of transformer upper end, so operate safety, labour saving and time saving, can promote labor efficiency to it is reliable fixed to guarantee that the generating line is arranged, guarantees that its and transformer upper end sleeve pipe keeps sufficient safe distance, can improve installation and resume work's speed.