Air velocity field and temperature field of cockpit will affect the pilots- thermal comfort and performance directly, which are important parts need to be considered in the design of cockpit structure and environmental control system. After full-size three-dimensional model of B737-800 cockpit being established, a commercial computational fluid dynamics(CFD) software Fluent was used to calculate the flow field and temperature field of cockpit in high-altitude night work. Then the average temperature evaluation and the predicted mean vote(PMV)on the thermal sensation scale were used to evaluate cockpit temperature environment. A questionnaire was given to the pilot to obtain cockpit air flow and temperature comfort subjective evaluation. The results of simulation and subjective evaluation both indicate the B737-800 cockpit is a comfortable environment at night at high altitude. Besides, the trunk and legs feel a little uncomfortable as a result of slight coolness. The agreement of simulation results and evaluation results validates the accuracy of the cockpit airflow thermal simulation.