Computer simulation has been one of the most important and advanced research fields in the materials science and engineering. It is playing an increasing important role in the studies of microstructural evolution during solidification of metals and alloys. In this paper, the recent progress in computer simulation of solidification microstructures is briefly reviewed. Various models including deterministic and stochastic approaches for the prediction of solidification microstructures are compared and assessed. Then, a modified cellular automaton ( MCA) model developed by the authors is introduced and its predictive capabilities are described by presenting some examples including the modeling of 2D & 3D dendritic growth, non-dendritic or globular microstructure evolution in semi-solid process, eutectic and peritectic microstructure formation, as well as the asymmetric dendritic growth features in the presence of melt convection.