In view of the limited configuration of multi-link planting mechanism at present, a complete multi-link planting mechanism library was constructed by means of graph theory. Firstly, based on the method of weighted fourth power matrix and weighted minimum distance matrix, the similarity feature code of vertices was obtained in the kinematic chain synthesis of linkage mechanism. In accordant with the uniqueness of the feature code, the similarity recognition and isomorphism identification of the kinematic chain were conducted. Secondly, the specific screen rule of the planting mechanism configuration was established based on similarity of vertices, and then the functional vertices for input link, output link and rack were determined. The mechanism topology library of six-link to nine-link was established: the number of 6-link 1-DOF KCs was 14, the number of 7-link 2-DOF KCs was 17, the number of 8-link 1-DOF KCs was 510, and the number of 9-link 2-DOF KCs was 917. Finally, the configuration of different links consisted of six-link to eight-link in the planting mechanism library was selected for kinematics modeling, and the new size of six, seven and eight-link planting mechanisms suitable for planting operation were obtained. The correctness of the configuration synthesis method was verified by comparing the theoretical results with the motion simulation results, which provided more optional configurations for the innovative design of diversified planting mechanism. The use of structural synthesis method is conducive to the innovative design of planting mechanism.