BaO-SiO2 and Al2O3-SiO2 dried gel powders were prepared by the sol-gel process using TEOS, aluminium nitrate and barium acetate as raw materials. By using these starting materials, beta-BaAl2Si2O8 (hexacelsian) powders with small particle size were obtained after calcining at 1000 degrees C. The effects of solvents and prehydrolysis of TEOS on the gelation were studied. The physical and chemical changes, and phase transformation of the gel powders for BaO[Al2O3]-SiO2 and BaO-Al2O3-SiO2 systems during heating were examined using differentia I thermal ana lysis, gas chromatography and X-ray diffraction. The particle sizes of the gel powders obtained were also observed by SEM and TEM.