Abstract:Bayesian Network has great advantages in solving the uncertainty and association fault in complex equipments,setting up the Bayesian Network Diagnostic Model according to AI-ESTATE Standard is of great importance to realize the goal of universality. Firstly,the main contents,architecture and six information models of the AI-ESTATE Standard are introduced. Secondly,extending process from Common Element Model to Bayesian Network Model is analyzed in the paper based on the analysis of Bayesian Network,at the same time,extending figure is given,each entity and attribute are introduced in detail. Finally,aiming at the problem that the EXPRESS language used in the standard has the disadvantages of less editing tools and poor utility,XML is used to describe the exchange document for its universal property,as a result,the diagnostic information are equipped with portability and interplay.