Traditional automatic control systems are deployed in independent control centers, while the power system is interconnected and controlled respectively. In order to simulate this feature, the global power flow calculation and power system closed-loop control for multi coordinated control centers is proposed. Some key technologies are introduced, including the standardized model combined/split technology, the continuous data section fitting technology, multi-user scheduling and parallel processing technology, the slave station simulation technology, etc. By comparing with the real-time system and dispatcher training system, the features of proposed method are described. Based on the proposed method, the China Southern Grid simulation system integrated for grid, provincial and district power system is constructed, which can be used to verify the coordinating control strategy among multi-level hierarchical control centers.