Investigations of the thermal evolution of the structural and dynamic properties of small cobalt clusters in melt are performed using molecular-dynamics simulations with a Finnis-Sinsclaire potemtial. The mean square displacements, atomic volume, and inernal energy, as well as the pair correlation function and bonded pairs, are obtained from quick and slow cooling simulations, respectively. The splitting of a second peak of pair correlation funcion is due to the presence of icosahedron-type clusters. The results demonstrate that the transition from a supercooled-liquid to a crystal is a discontinuous transition in structure, while the supercooled-liquid to glass transition is a continuous transiton in tructure. The physical picture of the tructure of metallic glass is a disrdered entanglement with a lot of icosahedar.