Recent studies on Pd L₃-edge X-ray Absorption Near Edge Structure (XANES) spectra for pure Pd small clusters show that the spectra are greatly influenced by hydrogen adsorption and absorption. In this paper the full multiple scattering method is applied to study the difference in measured spectra. The calculated XANES spectra are not so sensitive to the detailed positions and the electronic structures of the interacting hydrogen atoms, whereas they are sensitive to the induced structural and electronic state change in the host Pd small clusters. The size effect on the peak at ∼7 eV is well explained in terms of the induced lattice expansion after hydrogen absorption.