Abstract: The structural change in a Cu59 cluster from solid-state to melt during heating was investigated with the molecular dynamics simulations based on embedded-atom potential. Analyzing the local change in atomic structure in the 4 shells, which are determined by the atomic density distribution function with rising temperature, it was found that the Cu59 cluster structure changed in 3 stages due to the continuous interatomic position interchange during heating. First, a near-icosahedral structure takes place, which is composed of thirteen atoms and formed inside the cluster. Then, the atomic structure within every shell gradually changes disorderly. Finally, the molten-state Cu59 cluster is formed, of which the atoms are distributed within 3 shells.