Lifting device and liftable protective fence

The embodiment of the utility model provides a lifting device and a liftable protective fence. The lifting device comprises a screw rod, a locking piece, a sliding piece and a connecting piece. The locking piece is provided with a through hole, the through hole is used for containing the screw rod, the connecting piece is fixedly arranged on one side of the locking piece, the locking piece comprises a thread meshing piece, the thread meshing piece is exposed through the inner wall of the through hole, and the thread meshing piece is used for being connected with the screw rod in a meshing mode; the sliding piece is arranged on the other side of the locking piece and penetrates through part of the locking piece; when pressure is applied to the sliding piece, the sliding piece extrudes the threaded meshing piece so as to release meshing of the screw and the threaded meshing piece. According to the embodiment of the invention, the lifting devices can be arranged on the two sides of the protective fence, the over