Using classic particle dynamics simulations, the interaction process between an intense femtosecond laser pulse and icosahedral hydrogen atomic clusters H13, H55 and H147 has been studied. It is revealed that with increasing number of atoms in the cluster, the kinetic energy of ions generated in the Coulomb explosion of the ionized hydrogen clusters increases. The expansion process of the clusters after laser irradiation has also been examined, showing that the expansion scale decreases with increasing cluster size.