In order to reduce the oxidizing and volatilizing caused by Mg element in the traditional methods for synthesizing Mg2Sil-xSnx solid solutions, Mg2Sil-xSnx solid solutions have been prepared by Microwave-assisted Synthesis techniques. The heating behavior of Mg, Si and Sn fixed powder was investigated under microwave irradiation. X-ray diffraction (XRD) was used to characterize the powders. The results suggest that the temperature-rising rate is also dependent on the initial green density and higher green density provides lower heating rate while power setting are fixed. XRD patterns show that Mg2Sil-xSnx solid solutions have been well formed under microwave irradiation.