By two-stage solid phase reaction, a series of Mg2Si1−xGex continuous solid solutions were successfully synthesized at low temperature (823 K) for the first time. The product was single-phased without any oxide or carbide and the particle size was substantially reduced than that of the raw powders. X-ray diffraction (XRD) techniques were used to explore the products' phases and differential thermal analysis (DTA) to the changing tendency of heat quantity during the solid phase reaction. The influence of Ge substitution to Mg2Si1−xGex was illustrated by the changes of lattice parameter and the existence of the complete solid solubility between Mg2Si and Mg2Ge was established, too. © 2001 Elsevier Science B.V. All rights reserved.