Abstract: According to the simulation requirements of on-orbit maintenance task for manned spacecraft mission, we propose a mixed validation method which can simulate the influence of microgravity and vacuum. Our proposal includes the framework of the simulation system, and the modeling method of the cosmonaut, the extravehicular activity pressure suite, the robot arm model, and others. An actual mission is simulated and the difference between the simulation and the real mission process is analyzed. The results indicate the method is reliable for the maintenance design and optimization.