A tube coupler clamping and positioning tool comprises a first clamp arm, a second clamp arm and a screw fastening bar. The first and second clamp arms have respectively a first coupling end and a second coupling end that are hinged together. The screw fastening bar has two thread sections formed in different helical directions and runs through the first and second clamp arms with the two thread sections threaded respectively in the first and second clamp arms and the first and second compression ends of the first and second clamp arms opposing each other at a selected interval. Thus through turning the screw fastening bar via a torsional wrench, the interval between the first and second compression ends can be changed to tighten the tube coupler. Moreover, with the torsional wrench, strength of the fastening force and tightening force exerting on the tube coupler also can be controlled.
