The synthesis and microwave characterization of glass ceramic in the quaternary phase field of the MgO-CaO-Al2O3-SiO2 system synthesized by sol-gel method have been investigated in this paper. The glass powder was obtained by calcining the MgO-CaO-Al2O3-SiO2 xerogel, which was prepared from Magnesium nitrate hexahydrate (Mg(NO3)(2) . 6H(2)O), Aluminum nitrate nonahydrate (Al(NO3)(3) . 9H(2)O), Calcium nitrate tetrahydrate (Ca(NO3)(2) . 4H(2)O), and tetraethylortho silicate (TEOS). The powder was characterized by differential thermal analysis, thermogravimety and X-ray diffraction. The calcined powder was pressed, sintered at different temperatures, and then the sintered sample was studied with scanning electron microscope, X-ray diffraction patterns, and microwave properties measurement. (C) 2003 Kluwer Academic Publishers.