Structural change of a Au959 cluster supported on the MgO（100） surface at a low temperature of 10 K is investigated by molecular dynamics simulation based the on atomic interchange potentials of the metal/MgO interface, where the parameters are from the ab initio energies obtained based on Chen-Mbius inversion method. The analyses on paired atoms and pair distribution functions show that there exists a deformation process in the Au cluster to adjust the interatomic distance of the interface atoms, owing to the mismatching of the interatomic distancs in the cluster to those in the substrate. After the adjustment of atomic positions, the volume of the supported Au cluster becomes larger than its unsupported counterpart.