AgGa1-xInxSe2 polycrystals were synthesized by the method of mechanical oscillation and temperature oscillation. X-ray diffraction spectra of polycrystal powder are conformable with the JCPDS cards. Lattice constants a and c calculated from the XRD were found to obey Vegards law. The melting point of AgGa0.8In0.2Se2 obtained by means of differential scanning calorimetry (DSC) is 796.53 ℃. The DSC curve also show that there are no other transformation points below the melting point. The results indicate that polycrystalline materials synthesized by the method mentioned above are high-quality and can be used to grow single crystals by the vertical Bridgman technology.