Abstract: Case based reasoning is an effective method to solve design for assembly and assembly planning problems,while assemblies retrieval and indexing is a primary step to its application.A method of local matching of assembly models is proposed,which is based on subgraph isomorphism and case matching.An attributed adjacency graph is constructed to represent assembly models.The connection relations of assemblies are formally expressed and categorized.The pretreatment rules of the attributed adjacency graph of assemblies are defined.Then,the similar structures of assembly graph(subgraph) are matched by using Ullmann algorithm.And similarity calculation formulae of local matching of assemblies are given.Finally,an example is illustrated to verify the validity of the proposed approach.