This invention discloses a rotary clamping mechanism comprising a cylinder, a rotary member, and a clamping member, wherein the rotary member and the clamping member have shapes that gradually change; the rotary member comprises a first board, a second board, a first connection member, and a second connection member; a wall groove is arranged at the lower side of the inner wall of the cylinder; the rotary member and the clamping member can rotate in the cylinder to contract and compress.