To overcome the weakness in the data access and process of the current electric power dispatching automation system， an open data maintenance model is proposed. Its basic concept， design ideas and working theory are also researched. By expanding system's database sources and enhancing its processing capacity， the data maintenance model solves not only the information island problem brought by heterogeneous database， but also the defects such as low efficiency， overload， etc. It offers a favorable real-time platform for the safe operation of the dispatching automation systems. A real-world project is developed as an example of the open database maintenance model in electric power dispatching automation systems and conclusions are drawn.