The invention relates to a main transformer insulation paper vacuum sampling device, comprising a rotary sampling barrel; a ring-shaped cutting edge is arranged on the head of the rotary sampling barrel; the tail part of the rotary sampling barrel is connected with the outer ring of a sealed bearing, and the inner ring of the sealed bearing is connected with one end of a connecting pipe; the other end of the connecting pipe is connected with an air exhaust hole of a vacuum pump; the rotary sampling barrel is communicated with the interior of the connecting pipe; the connecting pipe is provided with a button used for breaking the air tightness of the connecting pipe. The main transformer insulation paper vacuum sampling device can be used for effectively and normatively sampling insulation paper which is used for fixing, binding and winding main transformer windings and leads in a main transformer.