In this paper,structural analysis software based on FEM and its intelligent consultantsystem(Front-End System and Modeling System )are presented.A new conceptual model ofknowledge based structural analysis system,which integrates modeling,numerical solvingand result interpreting and evaluating.is established using blackboard structure and truthmaintenance system. As an example of this model,a simple system KBSAP using Clan-guage based on the Software Environment of Finite Element Methods(SEFEM)was imple-mented.