Previous works indicated that Al particle surfaces could be modified by fine gamma-Al(2)O(3) grains, which can be used as a hydrogen-generation material, where the fine gamma-Al(2)O(3) grains were produced by the decomposition of the Al(OH)(3) phase in the mixture. In this work, commercially available gamma-Al(2)O(3) powder was directly used as the modification agent and mixed with Al powder and heat treated at an elevated temperature. It was found that the modified Al powder produced by directly using gamma-Al(2)O(3) has an obvious shorter time for complete hydrogen generation than that using Al(OH)(3)-produced gamma-Al(2)O(3). Microstructure analyses revealed that directly using gamma-Al(2)O(3) powder has a better coverage of fine gamma-Al(2)O(3) grains on Al particle surfaces than the Al(OH)(3)-produced gamma-Al(2)O(3). This implies that a uniform distribution of modification agents on Al particle surfaces is an important factor for the Al-water reaction dynamics.