Abstract: The relation of the morphology of grains in 430 stainless steel with microstructural parameters, such as grain nucleation density, Gaussian decomposition parameters and Gibbs-Thomson coefficient, was studied based on the CAFE model. The effects of casting conditions, such as superheat and cooling intensity, on the solidification microstructure were also analyzed in this paper. It is found that the grain size and the columnar to equiaxed transition (CET) are both affected by maximum bulk nucleation undercooling and maximum nucleation density. As the Gaussian decomposition parameters and Gibbs-Thomson coefficient increase in an appropriate range, the primary dendrite arm space decreases, but the central equiaxed area increases. Besides, the central equiaxed area decreases with increasing superheat and cooling intensity, while the primary dendrite arm space shows no obvious change.