Novel faceted alpha-SiAlON micro-crystals were prepared by combustion synthesis with proper additives. These crystals exhibited various end shapes, including smooth flat hexagonal faces, pyramids bounded by six small isosceles triangles, and partial pyramids with the sharp roofs removed. The formation mechanisms of different crystal shapes were discussed, and a terraced epitaxial nucleation mode for alpha-SiAlON was proposed. By this nucleation mode, two interesting crystal morphologies were formed: a terraced tower structure and a T-like shape. Transmission electron microscopy results showed that the fast growth direction of rod-like alpha-SiAlON crystals was parallel to the C-axis.