Monte Carle method and embedded-atom potential were utilized to study the energetics and structures of high_temperature copper clusters, which contained 55 ato ms. First, we calculated the energetics and structures of Cu55 at 2 00?K.T he results that we got well accord with those Suleyman Ozcelik et al obtained. I t is shown that this method is reliable. Then, the system was cooled from 12000 ?K, in a step of 1000?K, the energetics and structures were measured while th e system reached equilibrium. At each temperature, the Monte Carlo Stepsare 10 6. From the simulation we found that above 10000?K, the system only contain a few atoms that are combined together and unsteady,so single atoms are getting more. Between 10000 and 6000?K, the structure of the system gradually changes to forming nucleating center, other atoms nucleated with nucleating center; Atta ined equilibrium at 5000?K, the system atom is already complete combinative tog ether without the monatomic, the energy is -11206?eV; Further lower the tempe rature, the system construction becomes from irregular、dissymmetrical to regula r、symmetrical forming a double icosahedral shape, the energy is -16850?eV; W ith visual displaying, a very clear evolving structural diagram was achieved wit h lower in temperature.