Abstract: The k-ε turbulence model, the species transport model and a user-defmed function are employed to simulate the dispersion of CO₂ contaminant in a manned spacecraft. The results are as follows. The 45° eject flow in the single cabin and the airflow exchange between adjacent cabins can have a highly effective transfer of species; the concentration of CO₂ near the cabin wall on the right or left side ofthe astronauts is a little higher than that in the other regions; the CO₂-purilying device Can satisfy the requirements of the CO₂ control when it is installed in another unmanned cabin. The study may provide some guidelines for organizing the CO₂ purifying devices and CO₂ sensors in manned space station cabins and for improving the airflow scheme.