From first-principles calculations based on density functional theory, we find that the recently synthesized beta(12) boron sheet is a perfect candidate for calcium-decoration and hydrogen storage application. In contrast to graphene where defects are required to capture Ca, the naturally formed hexagonal hollow ring in beta(12) boron sheet provides the ideal site for Ca adsorption, and up to 6H(2) molecules for each Ca atom can be captured with a desirable binding energy of similar to 0.2 eV/H-2. The gravimetric hydrogen density for Ca decorated boron sheet can reach up to 8.92 wt%. From the electronic analysis, it is found that both the orbital hybridizations and polarization mechanism play significant roles in H-2 adsorption and storage. (C) 2018 Elsevier B. V. All rights reserved.