The invention discloses a clamping device. The clamping device comprises a workbench, an upper die plate, sliding grooves, movable clamping blocks, two fixing and fastening platforms, a chip removal device, hydraulic supporting rods and a lower die plate. The workbench is in a cuboid shape. A first fixed clamping block and a second fixed clamping block are symmetrically and fixedly mounted on the surface of the left side of the workbench. The two sliding grooves are inlaid in the surface of the right side of the workbench. The movable clamping blocks are mounted in the clamping grooves. The two fixing and fastening platforms are mounted on the surface of the right side of the workbench and located on the right sides of the sliding grooves. Screw rods penetrate through the fixing and fastening platforms and are connected to the movable clamping blocks. The chip removal device is arranged in the middle portion of the workbench. The hydraulic supporting rods are connected in the gap between the workbench and the upper die plate. Oil guide pipes penetrate through the upper die plate and are connected with the hydraulic supporting rods. A hydraulic cylinder is fixedly mounted on the surface of the lower die plate. An oil delivery pipe is connected to the hydraulic cylinder and a supporting rod. The clamping device is high in practicality and easy and convenient to use and operate.