The potential impact of strong greenhouse effect of SF

6

on global climate has already caused arousedgreat concern.Degradation of SF

6

is an effective measure to treat SF

6

.In this paper

the effect of H

2

O volume frac-tion on the degradation of SF

6

based on packed bed reactor（PBR）is studied and analyzed from such two aspects asdegradatio

n efficiency and products.It is shown by the study result that H

2

O can produce a large amount of OH andH free radicals in the PBR.These active free radicals can react with the primary decomposition products of SF

6

topromote their decomposition and improve their degradation rate.It is found by experiment that when the volumefraction of SF

6

is 2%

the water vapor volume friction which is most beneficial to promote the degradation of SF

6

is 1%and its degradation rate reaches 95.69%.Meanwhile

the decomposition of H

2

O needs absorbing free electronsin the environment

thereby inhibiting the filament discharge in the PBR.The volume friction of H

2

O also has agreat influence on the volume friction and selectivity of SF

6

degradation products.The increase of H

2

O volume frac-tion will increase the volume fraction of SO

2

and decrease that of SOF

4

.The study in this paper improves the under-standing to SF

6

degradation process and also paves the way for industrial applications.