Abstract: With the research methods of the holism and reductionism of system science, the ironmaking/steelmaking interface characteristics of the six typical processes were analyzed from time, temperature, mass flow quantity, production plan, the effect of hot metal pretreatment, energy consume, environment pollution and so on. A relative superiority of the ironmaking/steelmaking interface of the six different processes was pointed out. The process ofdesiliconization, desulphurization and dephosphorization is only suitable for the process section of the large-scale blast furnace and the large-scale converter, and the process of dephosphorization in BOF is superior. Canceling the mixer and using the same ladle from BF to BOF are the developing direction of the ironmaking/steelmaking interface.