A practical solution is presented for designing a high performance distributed real-time database， which delicately supports energy management system（EMS）. Based on traditional relational database model， this design scheme imports some novel concepts， such as table set and attribute set. So it supports both the physical model and the objective model that are defined in IEC 61970. It also supports multiple study modes and multiple calculation modes that characterize the EMS applications. The practicality of the design has been approved through a system test on a simulated electric network with 250 buses . The test result shows that 2 million read transactions per second is achieved in single table mode and 200 thousand read transactions per second is achieved in object oriented mode， also all the EMS calculations are finished within 400 ms.