Abstract: The design of the air environment control system for a maIlned spacecraft is related to maIly parameters. In this paper, an integrated simulation model of me air environment control system is built, including the cabin sub module, the crew sub module, the pressure control sub module, the temperature/humidity control sub module, and the carbon dioxide removal sub module. Using this simulation model, the air environment control system is allalyzed. According to the results, it is shown that the parameters of different sub modules of the air environment control system are coupled and their mutual effects caIl not be ignored. The variations of different parameters of the air environment control system under differem heat load ofair are analyzed. The upper limit of heat load of air is obtained, which could be used to determine the working pattem of the manned spacecraft. The work in this paper call be used in the designd improvement of the air enviroment control system of manned spacecraft.