Abstract: A 5A molecular sieve absorption column and a hot decomposing Mg bed are one of the effective means to collect and decompose HTO in glove box atmosphere.The performan ces of the 5A molecular sieve column and the hot Mg bed are measured.The results show that the column absorbs water vapour from air with efficiency up to 99.99%.No water in the output gases is detected even though the water content in the input gases is about 3.4×10 -3 ～4.2×10 -3, and the total water absorbed on the column is up to 162 g. In the hot bed, more than 99.9% desorption water from the column is decomposed though more than 80% magnesium in the bed is used up.