The invention discloses a knowledge base modeling method for an intelligent substation operation and maintenance system based on a semantic network. The method includes the steps that, a theoretical basis for modeling substation operation and maintenance system based on the semantic network is established; the concepts and ideas of ontology and the semantic network are used for reference, according to the requirement of an SCL in the IEC61850-6 standard for a object model, basic structures and logical frames among each first device, a corresponding secondary device and a corresponding communication device are analyzed, and a model foundation of semantic-network-based substation operation and maintenance expert system modeling is built; through the combination of the IEC61850-6 standard and the characteristics of the semantic network, a reasonable operation and maintenance system knowledge base model is designed in the three aspects of intelligent substation device configuration, IED configuration and communication configuration; finally, based on a CLIPS platform, the related model is verified. The method has the advantages that the use of the semantic network makes the structure of the knowledge base more systematic, the logicality and consistency of different concepts of the knowledge base are improved. and the purpose of improving the expansibility of the systematic knowledge base and the rule reuse rate of a rule base is achieved.