With development of oxygen enrichment and PCI technology, it will not render an applicable methodology to design blast furnace on basis of its hearth combustion intensity and volume combustion intensity. To that end, China’s blast furnace design needs to be systemized for its own in responding to the time. Furnace design has to satisfy its intensified production whenever required. The present thesis takes advantage of modern gas kinetics to analyze, in a scientific way, the factor in furnace intensified smelting process, that is, bosh gas index. It is to provide a guideline for blast furnace design in interest of establishing a new furnace design system.