To obtain Al alloys possessing the excellent hydrogen-generation performance with high efficiency/low cost via the hydrolysis reaction of aluminum with water, a series of as-cast Al alloys (similar to 10 g) alloying by 13 kinds of Ga-based low melting point alloys with different contents were prepared by the high frequency induction melting method under a high purity argon atmosphere. The effect of the content and composition of the low melting point alloys on the hydrogen-production property of Al alloys ingots with the tap water was systematically investigated. The relationship among the hydrogen production performance, the microstructure, and the phase constituents of these Al alloys was investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy disperse spectroscopy and differential scanning calorimeter (DSC). Compared with conventional activated Al alloys powders prepared by the ball-milling method, the as-cast bulk Al alloys show the same excellent properties of hydrogen production, i.e., the high hydrogen-generation ratio but slower and more persistent hydrogen generation rate. The preparation method of Al-alloy ingots is simple, convenient, low preparation cost and high efficient, compared with the ball-milling method, which shows the significant industrial application value and prospect. Besides, the activation mechanism of the Al-water reaction dynamics was revealed on the basis of the analysis of the microstructure, phase composition and related literature. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.