Abstract: The UV absorption curves of gaseous ozone in oxygen at different time and diffe rent temperature were investigated by using UV 2501 spectrophotometer. Rules of ozone decomposition in oxygen in normal condition were obtained. The results in dicate that the self decomposition reaction of ozone in oxygen is approximately the first order reaction. The average apparent activation energy is about 2.43 ×104 J?mol-1 . The velocity constant is k =95.6 exp(-2.43×104/ R T ) min-1 . The reproducibility of related date appeared good. It is concluded that the half life of ozone in oxygen is much longer than in atmosphere in evi dence.

Key words: decomposition rule, half life, ozone