Abstract: According to the need of spatial planting trajectory, a new kind of transplanting mechanism with helical elliptical gear trains was put forward based on the traditional transplanting mechanism with planetary gear trains which was used widely in high-speed transplanter. After analyzing the mechanism structure, the key parameters used to determine the planting trajectory were solved as well as the kinematic model of the mechanism based on D-H transformation matrix. The kinematic characteristics such as the side offsets of trajectory and the velocity of seedling needle were studied by the program developed on the basis of the theoretical model, and a set of optimal parameters was obtained by the method of human-computer conversation. Finally, virtual prototype test was carried out after finishing the structural design, the results of which showed that the new transplanting mechanism met the working requirements of wide-narrow distance rice transplanter.