As a useful approach the reverse microemulsion method was used to prepare the high thermal-stabile alumina-substrate materials with high surface area at high temperature. After calcined at 1100degreesC for 10 h, alumina, barium-doped alumina, and silicon-doped alumina synthesized by the reverse microemulsion method exist, still as the transition alumina phase including gamma-phase, delta-phase and theta-phase; their particles are nanometer-size and rod shape, the size distribution of its particle is very uniform, and their BET surface areas remain 52, 90 and 175 m(2) g(-1), respectively. This method claims its superiority at two points: the raw materials are inorganic salts which are cheap and obtained easy, and the synthesis procedure is simple and easy to perform. As the comparative examples, three samples above prepared by the sol-gel method exist mainly as alpha alumina phase and their BET surface areas are 20, 24 and 117 m(2) g(-1), respectively. (C) 2004 Elsevier B.V. All rights reserved.