As the command center of an aircraft，the importance of cockpit is obvious. The air distribution in the environment of cabin has very large effect on the pilot’s body health and normal operating. This paper establishes the threedimensional cockpit model of a certain civil aircraft. The computational fluid dynamics software FLUENT is used to numerical simulation after setting some reasonable assumptions and simplifications, then the thermal comfort of various working conditions is evaluated based on PS model. It is found that the best condition is that when the total supply air is 0.08m3/s, the side supply air accounts for 40% and the flow direction perpendicular to the outlet. At this time, the surrounding air temperature and speed of pilot and observer meet the requirements of the human body comfort. The simulation results can provide reference for the design of cockpit air distribution.