It is known that metal-doped C-60 molecule has suitable adsorption energy for H-2 adsorption/release around room temperature. However, the gravimetric storage capacity achieved on solid samples is too low (<1 wt%). In this work we study the hydrogen storage property of a metal-doped C-60 derivative, K2PC61BM, with density functional theory calculations. The complex of K7PC61BM is selected because it has been observed experimentally. The calculations are performed for an isolated K7PC61BM molecule, but the limited size of interstitial space for solid phase is taken into consideration in finding the adsorption structure. It is found that K7PC61BM can at least adsorb 31H(2) molecules (5.07 wt%) due to a compact adsorption structure. The averaged adsorption energy is 0.119 eV/H-2, indicating a desorption temperature near room temperature. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.