Fixing device for workpiece

The invention belongs to the technical field of tooling equipment and provides a fixing device for a workpiece. The fixing device comprises a base, wherein the base is provided with a lug boss which is inserted into a hole formed in the workpiece; a thread hole is formed in the top of the lug boss; a wedge is further inserted into the hole; the wedge is at least detached into two structures alongthe peripheral direction; the outer diameter of the wedge is the same as the inner diameter of the hole; a tapered hole with a big top and a small bottom is formed in the wedge; a tapered sleeve is inserted into the tapered hole; a pressing plate is arranged above the tapered sleeve; and when a bolt penetrates through the pressing plate and the tapered sleeve in sequence and then is screwed into the thread hole, an inner wall of the hole is tightly pressed by the periphery of the wedge, so that the technical problem that an existing workpiece with a special shape is difficult to fix by utilizing a clamping device is s