Molecular dynamic simulation has been used to study the microstructural change of Cu0.6Ni0.2Fe0.2 consisting of 8788 atoms (5272 Cu, 1758 Ni, and 1758 Fe atoms) during the cooling process. The influence of temperature on the microstructural properties is studied in detail through the atomic potential energy, the radial distribution function, the number of types of atoms present in the sample, the distribution of coordination number, and simplex distribution. Simulation results indicate that a crystalline phase transition occurs when the sample was cooled. The range of transition temperature is the range at which the atomic potential energy changes dramatically. This sample consists of facecentered cubic (fcc) and hexagonal closed packed crystals alternated with amorphous structures. The number of the simplex with radii larger than 1.9 Å decreased rapidly as the sample changed to a crystalline state.