Abstract: A micro-modeling method (MM) for the quantitative prediction of the shrinkage cavity formation in SG iron castings is proposed. The mathematical models describing the volume changes during the solidification of spheroidal graphite cast iron are established based on the models of solidification kinetics. The shrinkage cavity formation of T-shaped SG iron castings is calculated with MM method. The calculated results are compared with the experimental results. It is shown that the predicted size, shape and distribution of shrinkage cavity by MM method are in good agreement with the measured results.