Information integration can be divided into five levels， i.e.， hardware integration， data integration， software module integration， business process integration， and application access integration. In order to realize the information integration of various application systems in a power dispatching center， this paper proposes specific and detailed integration schemes for the five levels. The hardware integration scheme can be realized by using virtualization technology， and the hardware and operating system can be virtualized for different applications based on the VMware ESX Server platform. The data integration scheme can be achieved by establishing a data center which accords with the characteristics of power system data. The software module integration program can be carried out by establishing the component library， which is used to manage， develop and reuse the software components. The business process integration can be realized by introducing a standard work flow management system， connecting the“business process breakpoints” of the internal or external information systems， so as to form a complete fully-automated business process. The application access integration scheme can be realized by using Portal technology and Web services technology to achieve the unified access and integration of various application systems.