Abstract: An Object Oriented Finite Element Modeling Expert System (OOFEMES), developed by combining the principle of object oriented programming and logical based reasoning is presented. The design and implementation of system function and structure are emphasized, which include the classification, organization and representation of domain knowledge, as well as the associated reasoning and computation techniques. A model correction diagram, taking into consideration the structural irregularity of aircraft structure is given. Through application example, it proves that the developed system is useful and effective for the analysis of aeronautical structures.