In order to achieve the integration of EMS and DMS,three feasible construction modes including Centralized Integration,Distributed Integration and Decentralized Integration are analyzed.A new construction mode and technical scheme as Integrated Power Grid Dispatching and Controlling System (IPGDCS) is proposed,which includes key technologies as integrated system support platform,distributed SCADA,integrated analysis and decision support,and integrated power grid model center.Comparing the former construction modes and technical schemes,it is concluded that different dispatching/distribution automation system integration patterns should be adopted in different scale of power grid so as to achieve the best technical and economic benefits during its whole lifecycle.