In order to study the aluminum-water reaction characteristics of PVA-nAl/HTPB， the PVA-nAl/HTPB composites were prepared by dispersing nAl/HTPB in the polyvinyl alcohol （PVA）， which was obtained by physical cross-linking method. In order to explore the aluminum-water reaction mechanism， the aluminum-water reaction characteristics of the polyvinyl alcohol-nAl/HTPB with 0.1 mol·L^-1 NaOH solution at different temperatures （25， 40， 55， 70， 85 ℃ and 100 ℃））were investigated and the residue after the aluminum-water reaction were characterized. The results show that the maximum hydrogen production and rate of PVA-nAl/HTPB is 76 mL·g^-1 and 80 mL·g^-1·min^-1， respectively， which is higher than that of PVA-nAl. The product of the aluminum-water reaction is aluminium oxyhydroxide （AlO（OH））.