Abstract: A new seed meter device with combined suckers has been developed and used for wheat precision spacing plant in field. The seed meter includes a stationary disk in which there is a spiral slot consisting of three arcs. First, the equations of the spiral slot curves were given. And then, kinematics and dynamics of a wheat seed moving along the spiral slot were analyzed. The results indicated theoretically that the performance of monoseed of the seed meter was affected by the velocity, figure and size of the combined sucker. Finally, the calculating method of the critical vacuum of the seed meter was also discussed in this paper.