Abstract: In order to reduce the possibility of fire hazards in oxygen-enriched atmosphere, the burning rate of thin materials such as filter paper, cotton fabric and Dacron khaki in low barometric pressure and oxygen-enriched atmosphere was studied experimentally. The results show that the burning rate increases significantly with increasing altitude when the partial pressure of oxygen is constant. It is indicated that fire hazards will be caused in high altitude if the oxygen partial pressure is increased up to the oxygen partial pressure under the condition of the standard atmospheric pressure. The maximum safe concentration for oxygen-enrichment in high altitude was obtained from the analysis of experiment results.