Abstract: The characteristics and the requirements of the distributed system simulation platform for spacecraft are analyzed, including the characteristics of the multi-operation system, the hybrid architecture and the distributed structure, the model management, the experimental and simulation runs, the data management, and the design of the entire simulation platform. The proposed platform can be used under both the numerical and semi-physical simulation conditions. Comprehensive simulation validation requirements for the schematic design of the spacecraft are satisfied. And the commercial or proprietary software can be conveniently accessed to the platform. A simulation example of manned spacecraft is demonstrated to validate the functions of the platform and to its generality.