Aluminum based complex hydrides are interested in hydrogen storage materials. In the complex hydrides, Na3AlH6, CaAlH5 and AlH3 have a common crystallographic feature with AlH6 octahedra in spite of the chemical compositions are different. Na3AlH6 shows isolated AlH6 octahedra and CaAlH5 shows zigzag chained AlH6 octahedra. On the other hand, different crystal structures of AlH3 with different bonded AlH6 octahedra have been reported. Although those crystal structures have been clarified, those vibrational properties of different bonded AlH6 octahedra, which are a role of secondary structure, are unknown. Therefore, we will clarify the difference from comparative studies of Na3AlH6, CaAlH5 and AlH3 systematically measured by inelastic neutron scattering (TOSCA) combined with first-principles calculation.