The utility model discloses a special wrench for a butterfly nut of a grounding terminal. The wrench comprises a casing pipe, wherein the inner diameter of the casing pipe is larger than the outer diameter of the butterfly nut; two oppositely arranged clamp grooves are formed in the bottom end of the casing pipe; the size of each clamp groove corresponds to that of each side wing of the butterfly nut; a through hole transversely penetrating through the casing pipe is formed in the upper part of the casing pipe; and a rod-shaped rotary handle is mounted in the through hole. The special wrench for the butterfly nut of the grounding terminal is simple in structure and convenient to use, and the butterfly nut can be conveniently dismounted and mounted; and during working, all that is required is to nest the side wings of the butterfly nut into the clamp grooves, then the butterfly nut can be mounted or dismounted by rotating the rotary handle, moreover, during a fastening process, the clamp grooves are directly matched with root parts of the side wings, and torque born by the side wings is obviously reduced, so that the side wing deformation can be avoided.