To further optimize the trajectory and pose of planting nozzle as well as the geometrical shape of hole digged out by planting nozzle, which could improve the seedling erectness rate of seedling transplanting, a combinational design of planting mechanism driven by twostage planetary noncircular gears was proposed. 25 different kinds of planting mechanisms were designed by using deformed ellipticconjugate noncircular gears, deformed eccentric circleconjugate noncircular gears, deformed Pascal curve noncircular gears, deformed Fourier curve noncircular gears and deformed sinusoidal noncircular gears. General mathematical model of planting mechanism driven by planetary noncircular gears was built, and the general model was substituted into the proposed multiobjective parameter optimization model of rotary seedling planting mechanism. According to conditions of planting agriculture, the types of planting mechanism and the corresponding parameters which met the perfect planting requirements were got by optimizing. One kind of planting mechanism driven by planetary eccentricelliptical gears was compared with planting mechanism with planetary deformed elliptic gears. The result showed that the planting mechanism designed by many kinds of noncircular gear pairs had better performance. According to the types of planting mechanism and the corresponding parameters which were got by optimization, structural design and prototype development were carried out, then the experiment of kinematics with highspeed camera and the experiment of simulating the field planting were carried out. The comparison between the trajectory, pose and speed of planting nozzle obtained from highspeed camera experiment and theoretical calculation showed that the structural design was reasonable, the machining precision met the requirements and the test bed can realize expected principle projects. The simulation experiment in field planting shows the planting mechanism has high seedling erectness rate of 95%.