Abstract: In order to study the influence of the ventilation conditions on the characteristics of the fire flow field in the manned spacecraft, a physical model of the spacecraft sealed cabin in the microgravity environment is established. The numerical simulations are made for the distributions of the temperature and the smoke concentration in the cabin for different ventilation angles of the air supply(θ=0°, 45°, 60°) when the fire source locates at the center position. It is shown by analyses that the velocity field varies with the ventilation angle, with different temperature distributions inside the cabin. The smoke in the sealed cabin is more easily discharged when the ventilation angle θ takes the value of 45°or 60° rather than 0°. The simulation results can provide a reference for the installation of fire detectors in the manned spacecraft sealed cabin.