La1.5Mg17Ni0.5 hydrogen storage material was prepared by hydriding combustion synthesis (HCS) or mechanical alloying (MA). It was found that the hydrogen absorption properties of La1.5Mg17Ni0.5 prepared by MA are better than ones by HCS. La1.5Mg17Ni0.5 prepared by MA possesses high hydrogen storage capacity of 6.73 mass% at 523 K for less than 1 min and can absorb 4.92 mass% hydrogen at 423 K. The improvement of hydriding properties can be ascribed to the nonacrystalline formation and appearance of defects and strain during the process of mechanical alloying.