A method to simultaneously tie double-α-knots by using two bill hooks was put forward. Driven by a toothed disk with a symmetric intermittent gearing and a cam groove, the two bill hooks of the double-α-knot knotter rotated intermittently in the opposite direction at an identical speed and the arm swung in accordance with the regularity of holding the strand, pushing the loop and cutting the strand. The transmission scheme to implement sequentially the holding of the strand, the cutting of the strand, the pushing of the loop and the return of the knotter by transforming the rotation of the cam to that of the oscillating of the arm was determined according to the demands of the baling. The curve equation of the cam profile was established by means of the kinematic inversion. A detailed curve of the cam profile was obtained by programming in Matlab and the force transfer characteristic was analyzed. A knotting test rig was developed. The results of simulating the baling process on the test rig indicated that rigorous synchronization of motion of the two α-knot knotters driven by the toothed disk and their corresponding force transfer met the requirements of the matching of the structure, the position and the motion of double-α-knot knotter.