To reuse the 3D CAD model, a new method of 3D CAD model retrieval based on feature adjacent graph is proposed. First, a representation of feature adjacent graph for the CAD model is extracted by automatic identification-based and interactive identification-assisted. Next, the vertex product graph of the two CAD model’s feature adjacent graphs is constructed, and then the ant colony algorithm is employed to detect the maximum-cliques in the vertex product graph. At last, the similarity of the models is calculated by comparing the maximum-cliques. Experimental results show that this method can realize the 3D CAD model retrieval and its efficiency meets the requirements of applications.