Abstract: The realtime digital simulator(RTDS) has been widely used as an advanced tool of research and testing.Its modeling interface and running interface are separated, furthermore, its wiring diagram and monitoring data are separated on different interfaces, which makes RTDS inconvenient to be used. A graphic platform similar to EMS style is developed, which can exchange data with RTDS correctly and realtimely. By using the platform, the simulation process of RTDS can be monitored and controlled easily. Functions, software structure, main data structure and program flow of the system are introduced. A 220kV power grid model with two generators, doublecircuit transmission lines and dynamic load is tested. The testing result shows that the system meets the design requirements.