Molecular-dynamics calculations are performed to study the structural changes of a binary Mg-Al alloy cluster containing forty-five Mg atoms and twenty-four Al atoms being at lattice positions of the Mg17Al12 phase on heating within the framework of the Finis-Sinclair potential.The structurally changing processes of this binary cluster involves different stages being identified by pair analysis, pair distribution functions, and atom density profiles as well as atom packing in different regions.Concerning the locally structural changes, the obtained results reveal the following scenario in our simulations.The atoms in this cluster can keep their packing patterns in a low temperature regime.As the temperature is increased, a few of Al atoms on the cluster surface adjust their positions.Then, the Mg and Al atoms interchange their positions in the surface and sub-surface regions.Here the Mg atoms move into the exterior of this cluster, whereas the Al atoms into the interior.With increasing the temperature further, more and more atoms in the outer part of this cluster are packed into different patterns from those in the low temperature regime when the atoms in the inner part of this cluster keep their stably packing patterns.In high temperature regime, the shape of this cluster is greatly changed accompanying with the formation of locally icosahedral structures.