Abstract: Fault tree (FT) has been widely applied in rapid location of system faults.However,lacking of accurate semantic information makes it hard to avoid the problem of duplicate construction.This paper introduced ontology into fault tree domain and studied how to construct a FT domain ontology and SWRL.First,it proposed a method of know-ledge representation of FT with Web ontology language OWL and constructed a FT domain ontology which is shareable,reusable and extensible.Second,it transformed the logical relationship among events of FT into semantic Web rule language(SWRL).Finally,it put these SWRL rules and the FT ontology into an inference engine JESS.Then new knowledge is produced and it is exploited for the rapid location of system faults.The causes of events can be rapidly and efficiently located in FT.The experiment proves the correctness and effectiveness of proposed method.It can resolve the problem of duplicate construction of FT without any influence on the rapid location of system faults.

Key words: Ontology,Fault tree,SWRL,Inference