This paper studied the photo-dissociation and photo-oxidation of CF2ClBr vapor at 253.7nm. The CF2ClBr-O2 system under photo-dissociation condition gives major products such as CF2O, Cl2, Br2, minor ones e. g. CO2 and SiF4. The dissociation of CF2ClBr is a first-order reaction and the corresponding rate constant is about 1.89×10^-^5s^-^1. The apparent quantum yield of CF2ClBr is about unit. Based on the experimental results, the photo-dissociation process, the photo-oxidation mechanism of CF2ClBr and the change of CF2ClBr after being delivered into the stratosphere were discussed.

Key words: PHOTOOXIDATION, METHYL BROMIDE, CHLOROMETHANE, FLUOMETHANE, DISSOCIATION