Based on a large number of integration testing of secondary equipments in smart substations, the limitations of current integrated testing are analyzed to propose a new kind of integration testing mode for smart substation based on the testing platform, which will improve the efficiency of integration testing by enhancing the level of testing device and simplifying part of testing process. Through the analysis on the requirement of integration testing, the new system architecture for integrated testing platform has been designed with specific technical indexes, which is based on closed-loop tests of grid static fault simulation and takes the scalability, openness, and automated tests as the design goal.