Abstract: The inert Al2O3 with α phase and high surface area was synthesized from Al(NO3)3?9H2O and urea by microwave radiation. The preparation conditions were studied. The NiO/inert-A12O3 catalyst with large surface was prepared by impregnation and its performance of selective hydrogenation for the diene in the model gasoline was evaluated using a micro-reactor. By means of XRD, BET, NH3-TPD and SEM, the synthesized inert-A12O3 and its catalyst were characterized. The results show that the morphology of the inert α phase A12O3, to a certain extent, is the fragment shape structure with surface area greater than 200m2/g. The suitable synthesis conditions are: mole ratio of Al(NO3)3?9H2O/urea 2.5-3.0, the microwave power of 600W, the radiation time about 10 minutes. After the catalyst with 9.87% NiO on the inert-A12O3 is activated with H2, its hydrogenation conversion and selectivity for the diene in the model gasoline achieve both about 100% at atmosphere pressure, 80 ℃, LHSV of 6 h-1, H2/oil ratio of 100/1.