The structure and electrochemical properties of the La0.7Mg0.3Ni3.5 alloys laser sintered at different powers were investigated. It is found that all alloys contain three phases La3MgNi14 with the Ce2Ni7 structure, LaNi5 and LaMgNi4. The abundance of the main phase La3MgNi14 is 43, 68 and 63 wt%, respectively, when sintering power varies from 1000 to 1200 and 1400 W. The laser sintered La0.7Mg0.3Ni3.5 alloys can be activated to their maximum discharge capacity within three cycles. The discharge capacities of those alloys prepared by laser sintering at 1000, 1200 and 1400 W are 324.6, 352.8 and 340.5 mAh/g, respectively. The La0.7Mg0.3Ni3.5 alloy laser sintered at 1200 W has a best cyclic stability (S-100 = 58.4%) and high-rate dischargeability (HRD800 = 79.4%) due to the high amount of the main phase La3MgNi14. (c) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.