NaBH4-NH3BH3 composites were prepared by high-energy ball-milling processes for hydrogen generation through hydrolysis. After ball milling, there were no new phases found in the XRD patterns of NaBH4-NH3BH3 composites. The experimental results demonstrate that when the molar ratios of NaBH4-NH3BH3 composites range from 1:4 to 2:1, these composites can release above 90% hydrogen in 30 min at 70 degrees C. Comparing with neat NaBH4 or NH3BH3, the hydrolysis properties of these composites are greatly enhanced. And the hydrolysis reaction mechanism is turned out to be more explicit as Na2B4O5(OH)(4)center dot 8H(2)O appears in the hydrolysis products. Since the preparation processes of these composites are simple and cost-effective and the hydrolysis of these composites achieves efficient hydrogen release, it is promising that this kind of composites can be applied in hydrogen generation. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.