A magnetic attractive conjunction mechanism of a rotating gripper in a clamping device in which the magnetic attractive conjunction mechanism is installed at one or both of a sector type cylinder-shaped rotating gripper and a flush socket with sector type recessed cylindrical sliding surface of a coupled clip jaw, to make the sector type cylinder-shaped rotating gripper attract and connect to the flush socket with sector type recessed cylindrical sliding surface of the clip jaw through magnetic force, so as to form a rotatable coupling which prevents from detachment and is easily removed, and the main components comprising: the materials for installing the sector type cylinder-shaped rotating gripper of the magnetic attractive conjunction mechanism or the flush socket with sector type recessed cylindrical sliding surface of the clip jaw are not limited to be magnetic, if the sector type cylinder-shaped rotating gripper or the flush socket with sector type recessed cylindrical sliding surface of the clip jaw, which are relatively coupling, are made of magnetic materials, the both are directly coupling and rotating; if one or both of the sector type cylinder-shaped rotating gripper and the flush socket with sector type recessed cylindrical sliding surface of the clip jaw, which are relatively coupling, are made of non-magnetic materials, the closed magnetic circuit is formed by magnetic materials additionally installed at the coupling surface along curved track of relative rotation rotation; characterised in that the sector type cylinder-shaped rotating gripper, which is installed in the flush socket with sector type recessed cylindrical sliding surface of a clip jaw to perform coaxially relative rotation, and the cylindrical arc surfaces of the two are tightly contact and sliding to form a coupling surface, in which a concave hole is installed at the coupling surface of one or both of the sector type cylinder-shaped rotating gripper and the flush socket with sector type recessed cylindrical sliding surface of the clip jaw, for installing a magnet to make the two to form a closed magnetic circuit and thereby attract and connect each other after coupling, and said magnet and the coupling surface are even, and a non-magnetizer is installed between the circumference of the magnet and the concave hole with larger aperture, so as to secure the connecting status of the magnet and the concave hole structure without interference the magnetic attraction and the relative rotation between the both; the above-mentioned installing method includes to secure through structural combination or gluing. the materials for installing the sector type cylinder-shaped rotating gripper of the magnetic attractive conjunction mechanism or the flush socket with sector type recessed cylindrical sliding surface of the clip jaw are not limited to be magnetic, if the sector type cylinder-shaped rotating gripper or the flush socket with sector type recessed cylindrical sliding surface of the clip jaw, which are relatively coupling, are made of magnetic materials, the both are directly coupling and rotating; if one or both of the sector type cylinder-shaped rotating gripper and the flush socket with sector type recessed cylindrical sliding surface of the clip jaw, which are relatively coupling, are made of non-magnetic materials, the closed magnetic circuit is formed by magnetic materials additionally installed at the coupling surface along curved track of relative rotation rotation; characterised in that the sector type cylinder-shaped rotating gripper, which is installed in the flush socket with sector type recessed cylindrical sliding surface of a clip jaw to perform coaxially relative rotation, and the cylindrical arc surfaces of the two are tightly contact and sliding to form a coupling surface, in which a concave hole is installed at the coupling surface of one or both of the sector type cylinder-shaped rotating gripper and the flush socket with sector type recessed cylindrical sliding surface of the clip jaw, for installing a magnet to make the two to form a closed magnetic circuit and thereby attract and connect each other after coupling, and said magnet and the coupling surface are even, and a non-magnetizer is installed between the circumference of the magnet and the concave hole with larger aperture, so as to secure the connecting status of the magnet and the concave hole structure without interference the magnetic attraction and the relative rotation between the both; the above-mentioned installing method includes to secure through structural combination or gluing.