The structural evolution of a molten Cu55 cluster embedded in face-centred cubic （FCC） bulk is simulated by molecular dynamics method based on the embedded-atom method potential through mean square displacement, pair analysis indices, and the average energy of atoms. The simulated results show that final structure of the embedded Cu55 cluster mainly presents local FCC structure at the quenching temperatures. During solidification, the atoms continuously interchange their positions, and the rearrangement of atom positions is sensitive to the temperature change. As the quenching temperature increases, diffusion abilities of the atoms increase. At 100—500 K, the formed FCC structures are stable, whereas at 700—1100 K, the local structures of the clusters fluctuate with time step increasing.