Clamping device and clamping method

The invention provides a clamping device and a clamping method. The clamping device comprises an engine seat provided with a track hole, a positioning plate fixed on the engine seat, a slide rod capable of sliding along the track hole, a plane clamping block, a cylinder piston, a cylinder, a support and a rotating mechanism, wherein the plane clamping block is connected to one end of the slide rod and is positioned on the same side of the engine seat as the positioning plate; the cylinder piston and the cylinder are connected to the other end of the slide rod; the support is fixed on the engine seat; the rotating mechanism is connected to the support; the rotating mechanism comprises a third-direction clamping part, a fixing part and a connection part; the third-direction clamping part and the positioning plate are positioned on the same side of the engine seat; the fixed part is connected to the support; the connection part is rotatably connected with the cylinder. The clamping device has the advantages of simple structure and accurate positioning.