Abstract: According to the model of ferrite growth by the carboning diffusion,the influenc of graphite nodules on the ferrtization was calculated when nodules are 2.2μm,3.42μm and 5.56μm in diameters respectively. The experimental 'results are compared with the caluculated ferritization curve and can be summarized as follows; at the middle broad region of ferritization curve the experiemntal results are in agreement with theoretical calculations quantitatively; at the beginning small region of the ferritization curve the experiemntal results are lower than those of the theoretical calculations,at the end region of the ferritization curve the experimental results are higher than those of the theoretical calculations. The smaller the nodules are, the more the experimental results are, being in agreement with theoretical calculation. The analysis shows that the experimental results are not so agreement with the theoretical calculations due to the induction period for the formation of ferrite core at the beginning small region, and to the microsegregation of the composition in the each graphite-Austenite eutectoid colony at the end region.