The invention discloses a screwdriver for a transformer tapping switch and belongs to the technical field of transformer tapping switch mounting and dismounting. The screwdriver comprises a box main body. The box main body is a ringlike box main body or a circular-truncated-cone ringlike box main body. The box main body comprises an outer box body and an inner box body. Two or more tool bar bearings are connected to the side wall of the inner box body in an embedded manner, wherein the tool bar bearings are located on the same horizontal line. A tool bar is connected to each tool bar bearing,and each tool bar is a vertical extending-and-contracting tool bar. A tool bit is connected to one end of each tool bar and located outside the box main body; and the other end of each tool bar is located inside the box main body. The end, located inside the box main body, of each tool bar is provided with a first-level transmission mechanism. Every two adjacent first-level transmission mechanismsare connected through a second-level transmission mechanism. The second-level transmission mechanisms are connected with a rotating handle. The rotating handle is arranged outside the box main body.The box main body in the corresponding shape is designed for the screwdriver according to the cylinder-shaped or circular-truncated-cone-shaped appearance of a transformer; and by means of the vertical extending-and-contracting tool bars and linkage design, the multiple tool bars can rotate at the same time so that screws can be mounted and dismounted.