A new kind of rotary plug seedling pick-up mechanism is designed on the basis of the analysis of current development situation. Kinematic model is established according to structure characteristic and working principle of plug seedling pick-up mechanism. Pitch curve equation of a new non-circular gear is built on account of three suitable transmissions ratio functions. The software of computer-aided analysis for this rotary plug seedling pick-up mechanism is developed. By human-computer conversation, structural parameters are carried out, which can meet the demand of driving. Based on these parameters, design of rotary plug seedling pick-up mechanism is carried out. A new kind of non-circular gear is put forward, which can get large range variable speed drive. Feasibility of new type of non-circular gear is verified after structure design and test of new non-circular gear is completed. At the same time, feasibility and stability of plug seedling pick-up mechanism are demonstrated on the basis of trajectory of virtual simulation and velocity curve of transplanting claw .