Abstract: To reuse 3D CAD models more efficiently,a new 3D CAD model retrieval method based on the ant colony algorithm is proposed in this paper.At first,a CAD model is represented by the attribute adjacent graph(AAG) with the B-rep information extracted from the model.Then,the ant colony algorithm is employed to detect the common subgraph in the corresponding AAGs of different models.The similar sub-parts are obtained according to the principle that the corresponding AAGs of two models have common subgraphs if the models have similar sub-parts.At last,the similarity of the models is calculated by comparing the similar sub-parts.Our experimental results show the proposed method outperforms the existing retrieval methods and can achieve the reuse of design and manufacturing.