Based on the DFT calculations within GGA approximation, we have systematically studied the ScBn (n = 1-12) clusters and their hydrogen storage properties. The results show that the maximal adsorption for H-2 molecules is ScB7 6H(2) structure with the hydrogen storage mass fraction about 9.11%. For ScBn.mH(2) clusters as n = 7 or 9-12, the average binding energies between 0.202 and 0.924 eV are suggestively conducive to hydrogen storage. In these medium clusters, the moderate adsorption strength can benefit application of hydrogen energy owning to easily adsorption and dissociation on H2 molecules at room temperature and 1 bar pressure. Furthermore, the absorption spectrum is also investigated from TDDFT calculation. An obvious red-shift of spectral lines at 4.2 eV or 5.6 eV is detected with the increase of number of H-2 molecules. It can be regard as 'fingerprint' spectrum in experiment to indicate adsorption capacity of H-2 molecules for ScBn.mH(2) nanostructures. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.