The utility model discloses a screw clamping tool which comprises clamping plates, a fixing box, a spring and a fastening rod. The fixing box comprises a box body and a fixing rod, the box body is provided with a perforation hole for a bar of a screwdriver to penetrate through vertically, one side wall of the inside of the box body is provided with the fixing rod, the side wall, opposite to the fixing rod, of the box body is provided with a threaded hole, one end of the fastening rod is screwed into the box body through the threaded hole so that the bar of the screwdriver can be fixed between the fastening rod and the fixing rod, and the bar of the screwdriver, the fixing rod and the fastening rod are located in the same plane. The clamping plates are two in number, penetrate through the box body to be located on two sides of the plane and can rotate relative to the box body, each clamping plate comprises a bending portion and a clamping piece arranged on the bending portion and extending out of one end of a screwdriver head, and the clamping plates are pivoted with the box body, so that when the other ends of the two bending portions are pressed, the two clamping pieces are away from each other, and the two ends of the spring are fixedly connected with the opposite faces of the two clamping plates in the box body respectively. The screw clamping tool can assist the screwdriver in fixing a screw at the screwdriver head.