With the development of power grid, traditional Spare Power Automatic Switchover became far from satisfaction of the grid operation. Area Spare Power Automatic Switchover(ASPAS) System, supported by automation, communications and internet technology, must go through rigorous testing before the closed-loop operation. The digital simulation technology of ASPAS test system acquires actual network collusion model by simulation, intend to analog the power-grid-operation. The SCADA collect measure data , send to the ASPAS module; the ASPAS module produce a strategy, send a switch control command to the SCADA, and renew the network operation status, creating a real-time closed-loop test environment. Test system compares the test and actual action process of ASPAS system by two ways—detecting the fault conditions of network or sending the SCADA simulation data into actual ASPAS system, providing a basis of the actual ASPAS operation.