This study simulated the bulk structure and surface energy of Al2O3 based on the density of states (DOS) and studied the synthesis and microstructure of one-dimensional Al2O3 whiskers. The simulation results indicate that the (001) surface has a higher surface energy than the others. The growth mechanism of Al2O3 whiskers follows vapor-solid (VS) growth. For the (001) surface with the higher surface energy, the driving force of crystal growth would be more intense in the (001) plane, and the alumina crystal would tend to grow preferentially along the direction of the (001) plane from the tip of the crystal. The Al2O3 grows to the shape of whisker with [001] orientation, which is proved both through modeling and experimentation.