Abstract: A sealed cabin model based on FLUENT for the pressure decay leak testing is established in this paper. The temperature change is calculated and analyzed against the environmental temperature, and the temperature distribution is obtained. The consistency between the computation model and the physical model is tested. The results show that the temperature distribution has an obvious effect on the pressure decay leak testing; near the average temperature, the linearity is evidenced with a very small error for the temperature compensation. Because of the change of the average temperature, the pressure decay should be compensated by the average temperature, and a number of temperature sensors on the upright should be placed according to some parameters, such as environmental temperature and the volume of sealed cabin.