In order to realize the automatic transplanting of potted eggplant seedling, a fully-automated potted eggplant seedling transplanting mechanism was designed based on a new type of non-circular gear which was proposed according to Newton interpolation method and the kinematic model of the mechanism was built. Orthogonal experiment with three factors and three levels was carried out according to the combination of agronomy and agricultural machinery. The experiment factors were the size of the pot tray, the volume ratio of the matrix and the water content of the bowl. The experiment indexes were the strength of picking seedling and the loss rate of the matrix. Test results showed that it is beneficial for the full-automated mechanism to transplant the potted eggplant seedling when the size of the bowl was 105, the volume ratio of the matrix was 1, the water content of the pot body was 70%~80%, the picking strength was 270N, and the loss rate of the mortar matrix was 294%. According to the mathematical model of transplanting mechanism and eggplant seedling agronomy requirements, computer-aided analysis and optimization software of the automatic transplanting mechanism was developed and used to obtain a set of parameters which satisfied the transplanting operation requirements. The optimized parameters were used for three-dimensional modeling and virtual simulation testing, and 3D printing technology was used to make a physical prototype for the trajectory verification test, which verified the validity and feasibility of the mechanism. The picking seedling tests and the transplanting tests certified the practicability of the mechanism.