The utility model discloses a clamping device, it relates to wringing machine technical field. The side is provided with the side frame frame respectively around going up frame and underframe, goes upframe and underframe front and back side and is provided with first flange and second flange respectively, and activity Board can rotate around first round pin axle through the first round pin axle and the frame attach that inclines, activity Board, has welded the seize in the middle part of the activity Board lateral wall, a plurality of inner chamber boards pass through the bolt to be fixed respectively on last frame, side frame frame, underframe, activity Board's inside wall, clamping cylinder passes through bolt fixed mounting on last rack mount board, second round pin axle passes the drive plate and fixes the drive plate on clamping cylinder upper portion with clamping cylinder push rod pin shaft hole, and second round pin axle head portion is provided with the stopping cover, and two the first arm boards are connected at the drive plate both ends, and the first arm board links to each other with second arm board, and second arm board and bottom mount connect into and seal wholly, welds the semicircle on the second arm board on the inboard. The utility model has the advantages of reasonable design, convenient operation is nimble, and the clamp is tightly effectual, and the practicality is strong.