The synthesis kinetics of Mg2Si intermetallic compounds (IMC) from the elemental mixture of Mg-Si powders was studied by using differential thermal analysis (DTA). The exothermic peaks were at 818 K, which indicated the synthesis reaction of 2 Mg + Si -> Mg2Si. The synthesis kinetics of Mg2Si was evaluated by the Ozawa method and KAS method, and its activation energy was calculated as 377.53 KJ/mol. Based on the data from DTA curves, the bulky materials of Mg-Mg2Si composite were prepared through solid-state reaction by using SPS consolidation process. From the results of XRD and SEM-EDS analysis on the composite materials, it was clarified that at low temperatures of 813 K and 833 K, Mg and Si powders never react completely, and the suitable temperature of solid-state synthesis by SPS should be about 853 K. (C) 2011 Elsevier B.V. All rights reserved.