Three-dimensional (3D) model reconstruction needs to resolve the association problem of precursory 3D process model and process drawing. An approach based on the attribute adjacency graph of the primitive combination units is proposed. By extracting the primitive combination units of process drawing and the projection drawings of the precursory 3D process model, the process drawing and the projection drawings was presented in an attribute adjacency graph. According to the attributes of the vertexes and edges, whether the two attribute adjacency graphs were isomorphism were judged, and the association problem of precursory 3D process model and process drawing was translated to the matching problem of attribute adjacency graphs. Taking the side plate part as an example, the experimental result shows that this method realizes the association of precursory 3D process model and process drawing.