In order to achieve the inhibition of hydrogen release from aluminum trihydride （AlH₃）， the hydroxyl polybutadiene （HTPB） was chosen as hydrogen absorber to undergo the hydrogenation reaction with unsaturated C═C double bonds under the catalytic action of CA catalyst， eliminating the hydrogen released by the decomposition of AlH₃ in time. The catalytic absorption characteristics of hydrogen released by AlH₃ under HTPB-CA system were studied by micron three-dimensional image microscopy （micron CT）， elemental analysis， thermogravimetry-differential scanning calorimetry （TG-DTA）， scanning electron microscopy （SEM）， X-ray diffraction （XRD） and other characterization methods. And the effect of hydrogen absorption on the decomposition of AlH₃ was further analyzed. It indicates that CA could catalyze the absorption of hydrogen released from AlH₃ in the HTPB system， inhibiting the generation of voids in AlH₃/HTPB grain which significantly prolongs its volume cracking time. The addition of CA extends the induction period AlH₃ decomposition in the AlH₃/HTPB at 70 ℃ from 6 days to 15 days. And the H content of AlH₃ of the AlH₃/HTPB/CA mixture is 8.94% after 203 days of aging at 60 ℃， while that H content of AlH₃ of the AlH₃/HTPB mixture is only 3.12%. It suggests the inhibition of the decomposition of AlH₃ after the hydrogen reacting with C═C double bond of HTPB to form C─H bond under the catalytic action of CA， demonstrating a hydrogen autocatalytic decomposition mechanism of AlH₃.