Multi-Agent technology is used to develop an efficient， reliable and flexible computing platform for a new generation of EMS（N-EMS）. A bidimensional federated architecture is proposed to organize multiple Agents in N-EMS. In this platform， concurrent mechanism and load-balance strategies are presented to improve the system's efficiency. Blackboard model is formulated as a media to realize the communication and coordination among Agents， which make all the Agents deployed in the N-EMS loosely coupled and can be plug-in and plug-out dynamically. The N-EMS， which is developed on this platform， has been put into practice in two provincial power grids. The field operation shows its effectiveness.