The utility model discloses a two -way overspeed device tensioner of double damping structure, the device includes: a base, the base has a pivot device, a first tensioning ware, first tensioning warecan rotate around the pivot center of this pivot device, a second tensioning ware, second tensioning ware can rotate around the pivot center of this pivot device, an elastic damping device, elastic damping device's both ends rotationally connect respectively in first tensioning ware with second tensioning ware, the 2nd damping device, the 2nd damping device set up in between base, first tensioningware and the second tensioning ware. The beneficial effects of the utility model are that: can improve the adaptation effect to four kinds of mode of MGU motor, car money that can the multiple difference of adaptation can also satisfy miniaturized light -weighted requirement by a wide margin.