In the dispatching system， the power network is in general monitored and controlled hierarchically. The power network model and SCADA information for each dispatching system are relatively independent and a sort of isolated information exists. Based on the common information model（CIM） standard and scalable vector graphics（SVG） format， a method of combining these decentralized graphics and model is presented. By analyzing the structure of the gateway power network between the superior dispatching system and each subordinate system， the method combines the decentralized models and graphics of each system to form a whole and detailed power network model. Accordingly， an online system for combining the decentralized distributed models and graphics is built to achieve decentralized maintenance， centralized modeling and unified monitoring of the whole network. The test results show that this method can resolve the problem of isolated information among the dispatching systems.