In order to solve the problem of diagnosis knowledge sharing of circuit fault dictionary in practical application, firstly, on the basis of Common Elements Model in the AI-ESTATE standard, Fault Dictionary Diagnosis Model is built based on the AI-ESTATE standard, the problem of the portable diagnosis knowledge is preliminarily solved using the generality of AI-ESTATE standard in the field of fault diagnosis. To solve the problem that the EXPRESS language adopted by AI-ESTATE standard is limited in use, XML language is put forward to standardize the description of the established fault diagnosis model, sharing and reuse of the fault dictionary diagnosis knowledge is realized in a larger extent using the general and flexible scalability of the XML language.