In order to achieve intelligent and efficient of seedling grafting process, a new mechanical structure scheme regarding the fourdegreeoffreedom serial grafting robot is proposed. In view of the complexity of its structure, timing control and linkage operation, the module identification visualization method and design implementation with the architectural constraints is developed. Firstly, the design structure matrix (DSM) of the robot considering the specific architecture constraints is constructed, and a large community fast unfolding algorithm (LOUVAIN Algorithm) is used to realize the predivision of the robot architecture blocks. Secondly, the DSM is clustered by using an advanced genetic algorithms (AGA), and multiple sets of high modularity divisions are obtained, which form a group possibility matrix (GLM). The diagonal GLM (DGLM) is obtained by diagonalizing GLM. Finally, the visualization strategy for DGLM is developed, and the colored optimal module division result is obtained. The optimal design result shows that the fourdegreeoffreedom serial grafting robot should be divided into seven independent modules, and the modularity reaches 0.782.