Abstract: Taking heat transfer, flow of liquids, and solute diffusion into account, a three-dimensional cellular automata-finite element (3D CAFE) model was built to simulate the solidification microstructure of 430 stainless steel. Based on the model, the change laws of temperature, solidification fraction and grain morphology in the steel ingot were revealed during the solidification process. In the model, Gaussian distribution was employed to describe the relationship between the grain nucleation density and the degree of undercooling, and the KGT model was adopted to describe the dendrite growth. According to the Fe-C-17%Cr equilibrium phase diagram, the solidification path was determined, and the distribution of porosities and shrinkage cavities in the steel ingot was predicted. The temperature history and the final microstructure simulated by the model are in agreement with experimental results.