The invention relates to a license plate machining device comprising a machine body, a workbench arranged on the machine body, a character die frame containing character dies and a driving mechanism driving the workbench to conduct stamping upward or descend. The character die frame comprises an upper die frame and a lower die frame hinged to the upper die frame in a connected manner. The character dies comprise figure dies and letter dies. The figure dies and the letter dies are arranged to be polyhedrons. All the faces of each polyhedron are provided with figures or letters. Each polyhedronis provided with an installation opening penetrating through the polyhedron. The lower die frame is provided with a groove containing the character dies. The upper die frame is provided with an installation channel corresponding to the groove and penetrating through the upper die frame. The groove and the installation channel are both provided with installation rods for installing the character dies. The installation rods are detachably connected with the character dies. The side, corresponding to the lower die frame, of the upper die frame is provided with a containing cavity for containing alicense plate base plate. One side of the upper die frame is provided with an opening communicating with the containing cavity. The license plate machining device has the technical effects of being simple in structure, reducing workload of workers and improving production efficiency.