A 3 dimensional sinter process mathematical simulation model has been developed for the purpose to make it possible the designs of sinter process from the stereoscopic viewpoint. This sinter process model can calculate not only the progress of sintering reactions and the resultant changes in the bed structures such as pore ratio and minerals composition but also the qualities of produced sinter. Through a pot sintering test, this sinter process model was confirmed authentic and able to calculate also the distributions of sinters property such as minerals composition inside sinter cake. This sinter process model was used for the analysis of the effects of gas flow plate on the sintering performance.