a=21.448mm, k=0.958, α0=-36°, δ0=67°，φ0=20°, S=155mm，R=20mm。 Working principles and structural feature of the transplanting mechanism with planetary spur gears and elliptical gears were analyzed, and its kinematics models were established. Parameters optimization software based on human-computer conversation was programmed by programming language of Visual Basic 6.0. Based on the parameters software, kinematics property was analyzed and simulated, and the analysis found out that various structural parameters would affect kinematics locus and optimization objectives of the transplanting mechanism. Then structural parameters of the transplanting mechanism were gained, which could meet the demands of transplanting seedlings. They were a=21.448mm, k=0.958, α0=-36°, δ0=67°，φ0=20°, S=155mm，R=20mm.