The invention discloses an extra-high voltage autotransformer. The extra-high voltage autotransformer comprises a body transformation assembly and a voltage regulating compensation transformation assembly. The body transformation assembly comprises two body transformation core columns and two body transformation accessory columns, wherein the two body transformation core columns are arranged in parallel and connected in parallel, and the two body transformation accessory columns are arranged in parallel. A low-voltage winding, a medium-voltage winding and a high-voltage winding are sequentially coaxially arranged on the periphery of each body transformation core column from inside to outside in a sleeved mode in the radial direction of the body transformation core column, wherein the low-voltage winding, the medium-voltage winding and the high-voltage winding are mutually connected in parallel. The voltage regulating compensation transformation assembly comprises two voltage regulating transformation core columns and two compensation transformation core columns, the two voltage regulating transformation core columns are arranged in parallel, the two compensation transformation core columns are arranged in parallel, a compensation winding and a compensation exciting winding are sequentially coaxially arranged on the periphery of one compensation transformation core column from inside to outside in a sleeved mode in the radial direction of the compensation transformation core column, and a voltage regulating winding and a voltage regulating compensation winding are sequentially coaxially arranged on the periphery of each voltage adjusting transformation core column from inside to outside in a sleeved mode in the radial direction of the voltage adjusting transformation core column. The overall loss of the extra-high voltage autotransformer is small, and the extra-high voltage autotransformer saves energy and is environmentally friendly.