The traditional fault tree diagnosis and the script language analysis method are combined to design a circuit fault diagnosis model based on fault logic interpreter.The XML technology is employed to construct the fault tree,which is then reasoned logically by script language.An intelligent component for fault logic interpretation is created to explain the fault tree and the script language,all of which form a set of intelligent fault analysis model.After the successful software construction,the following establishment and maintenance of knowledge base and reasoning tests can be realized by electronic engineer and operator,which is clear in labor division.This power circuit fault diagnosis system is flexible and convenient in practical applications.