The invention relates to a calibrating platform of an ultra high voltage direct current mutual inductor. The calibrating platform comprises a calibrating system of the ultra high voltage direct current mutual inductor, a mechanical device and a power supply device, wherein the calibrating system of the ultra high voltage direct current mutual inductor is used for being connected with the ultra high voltage direct current mutual inductor to be calibrated to form a calibrating loop; the mechanical device is used for transporting the calibrating system of the ultra high voltage direct current mutual inductor and building the calibrating loop; and the power supply device is arranged on the mechanical device and used for supplying power for the calibrating system of the ultra high voltage direct current mutual inductor. The mechanical device comprises a bottom frame, two voltage doubling drums, a driving system and grading rings, wherein the bottom frame is hinged to the bottoms of the voltage doubling drums, and the driving system is used for driving the voltage doubling drums to rotate relative to the bottom frame so that the voltage doubling drums can switch between the vertical state and the folded state; the grading rings are arranged at the tops of the voltage doubling drums; and part of the calibrating system of the ultra high voltage direct current mutual inductor is arranged in the voltage doubling drums, and the other part of the calibrating system of the ultra high voltage direct current mutual inductor is connected with the voltage doubling drums. The calibrating platform of the ultra high voltage direct current mutual inductor adopts integrated platform design, can conveniently meet all work for calibrating the ultra high voltage direct current mutual inductor,and is suitable for test rooms and field calibration.