Molecular dynamics simulation is performed to study the cooling rate effects on the resulting crystallization microstructure of bulk liquid copper (homogeneous nucleation). Our studies reveal that mixtures o f the metastable hcp phase and most-stable fcc phase, in all sorts o f proportion and in various forms such as layering and phase separation, can be obtained by controlling the cooling rate. We have also found that, below the glass forming critical cooling rate, the ratio o f the number of fcc-type polyhedra to the number o f hcp-type polyhedra at OK decreases with increase of the cooling rate.