By improving spatial transmission project of Dknotter, a type of knotter driven by double gear-discs was presented. Spatial transmission of driving ropeholder was arranged on another side of knotter stand. It simplifies a set of angle relation of spatial crossed axle on the imported knotter stand as angle relation of plane intersecting axle, reduces processing difficulty of the knotter stand, overcomes the difficult design and manufacture problem of spatial crossed bevel gear profile on the imported knotter, and is easy to be manufactured in large quantities. By adjusting the transmission ratio between worm and helical gear to 1∶3, original ropeholding plate with four notches was changed into ropeholding plate with three notches. The structure model of the knotter driven by double geardiscs was built up after the motion sequences of driving ropeholder, knotter jaw and knife arm were matched. The contrast test of knotting motion with the imported knotter shown that the improvement of spatial transmission project of the knotter driven by double geardiscs is reasonable, moreover, the motion sequence matches design of ropeholder, and knotter jaw and knife arm are right. The ropeholding and ropecutting motions are even better than those of the imported knotter, and the rope is directly got into the notch of ropeholding plate and cut off in the middle of the knife. The knotting tests operated on indoor bench showed that the knotting rate of the knotter driven by double geardiscs may reach 100%. Further field tests of bundling straw will be executed to investigate the knotting rate and the reliability of knotter driven by double geardiscs.