With the development of digital design and manufacturing integrated technology, 3D CAD model has become the core media of expressing product design and manufacturing information, efficiently locating the desired model from massive candidates, fully exploiting and reusing the implicit knowledge had an important role in improving the mechanical design efficiency and quality in the agricultural equipment field. To effectively realize the reuse of design information of 3D CAD models in design domain, an effective subpart retrieval method of 3D CAD models merging with design semantics was proposed. Firstly, design feature was taken as the basic carrier of design semantic information, the 3D CAD model was structuralized and represented by using a feature attribute adjacency graph（FAAG）. Then, a multilevel feature descriptor capturing different levels of information for detailed part design was designed to establish the design feature similarity assessment model. Finally, the matched feature pairs were extracted by using the sub-graph isomorphism algorithm between the FAAGs of the query subpart and the part in the model library to calculate the similarity between matched subparts. Experimental results showed that the proposed method can effectively support subpart retrieval of 3D CAD models merging with design semantics for design reuse. The proposed research results can provide a novel reuse method of multi-granularity, precise and intelligent for the agricultural machinery digital design, and had an important role in improving the mechanical design efficiency and quality in the agricultural equipment field.