To meet the dry land punch planting needs, a gear linkage cam combination planting mechanism which is composed of planetary gear, planetary carrier, connecting rod, groove cam and plant apparatus was designed. Through the modeling software Pro/E, the virtual prototype model of the plant mechanism was established and it was imported into the rigid kinematics simulation software ADAMS. Simulating the trajectories of the two duck-billed when the motion parameter λ in different conditions as λ<1, λ=1 and λ>1, the results showed that only when λ=1 the motion of plant mechanism could meet the zero velocity for seedling motion requirements and get better seeding status, testing the correctness and rationality of the parameter selection and mechanism design. Taking the self-made automatic vegetable transplanter as experimental prototype and planting mechanism as the research object, the experiment has carried out in two aspects: the planting uniformity and the upright degree of pot seedling. Experiments showed that seedling distance error rate was only 2.22% and seedling perpendicularity was good, proved that the designed planting mechanism could meet the planting requirements.