In order to early detection and better prevention of the in-flight fire, two different materials of typical passenger clothes were selected as samples to carry out a series of experiments at Kangding Airport and Guanghan in Sichuan, where the corresponding environmental pressure is 61 kPa and 96 kPa, respectively. During the experiments, typical parameters of the mass loss, flame shape, smoke density and smoke components are record and investigates the effect of different pressures on burning characteristics of the two 7typical passenger clothes. The results show that the mass loss ratio of two materials under 96 kPa is equal to that under 61 kPa. While the flame height increased with the decrease of pressure and the proportion of blue flame was higher than 96 kPa under 61 kPa. The change rate of smoke density under 61 kPa reached the peak value before that under 96 kPa. However, during the whole process, the change trend was nearly same. Moreover, the concentrations of CO and CO2 are quite different for the two pressures. It is concluded that there is a significant effect of the pressure on the combustion of passenger clothes in different scenarios.