Based on the usual chaotic-weighting first-rank local-region forecas ting model, a modification is made for the predictor in matrix and vector simulation instead of single variant. Then the modified forec asting model is applied to pr edict silicon content in molten iron of the medium-sized blast furnace in China, and good results are obtained. Finally, we find that the value of Kolmogo rov entropy has a great effect on the hitting accuracy of the prediction .