Abstract: The demand for real-time data communication between multiple grid dispatching systems for notification,alarm and operation information in the interconnected large power grid is getting increasingly strong.But the message transmission services provided by the message bus in the grid dispatching system are confined to the local area of single systems for lack of common and efficient technical means for wide-area real-time information exchange between multiple systems. The characteristics of the current message bus are analyzed.On this basis,the wide-area message bus is proposed for wide-area real-time data communication.The architecture of wide-area message bus based on electric power dispatching data network is studied.Key technologies in the architecture,such as subscription,synchronization,monitoring,pushing,tracking and reliable message transmission are described. Wide-area message bus has established a real-time message transmission mechanism penetrating through the multiple grid dispatching systems,which is able to effectively enhance versatility,reliability and high efficiency of message transmission between wide-area applications.