Condition-based maintenance in the wide area is one of the important research subjects of the electric power system. In order to realize the community cooperative maintenance decision and based on an analysis of the status quo and demand of the maintenance network， the system framework of multi-knowledge， multi-method， multi-information， multi-resource based on the knowledge grid is constructed and the method of knowledge modeling is studied. Being managed and dispatched by the knowledge grid platform in a unified manner， the resource nodes are open to each other and the resource information is shared to proffer different power plants， manufacturers and research units the service information needed. It is conducive to improving the diagnosis and management of the maintenance decision support system，reducing its cost and increasing its efficiency， thus providing a feasible means to implement condition based maintenance step by step.