Most steel products are made by the casting process which is one of the oldest and most widely used in the manufacturing process. Solidification is a phase transformation from a liquid to a solid. Most metallic materials are manufactured by the casting processes based on the principle of solidification because of its high productivity. Since the mechanical properties of as-cast products mainly depend on the microstructure characteristics such as primary dendrite arm spacing (PDAS) and second dendrite arm spacing (SDAS), the industries are trying to control the formation of microstructures. However, the dynamic evolution of the microstructure is hard to be observed experimentally and be predicted by only conventional macroscopic analysis. Therefore, many numerical models have been developed to predict and control of the microstructures formation in solidification. In this work, a lattice Boltzmann method (LBM) and cellular automata (CA) coupled model has been constructed to predict the microstructure formation during solidification.