The Reheating furnace is the major energy consumption item of equipment on a rolling steel production line within a metallurgical enterprise. Creating an optimized control system for the reheating furnace by using industrial controlled technology to control the temperature of the furnace, is the main method to promote reheating efficiency and reduce energy consumption of the furnace. The radiation coefficient of the furnace chamber is an important parameter of a reheating furnace control system. The quality of the control system is influenced directly by the coefficient. However, because that that parameter is a time based variable and the exact value of it is difficult to measure, it is settled as a constant in existing control system. As a result, the temperature of the steel slab can not be maintained accurately and output quality of a slab from a reheating furnace can not be assured. In this article, the technological process for a metallurgical reheating furnace has been analyzed, and the temperature distribution model of a slab in a reheating furnace has been built up by using the heating transfer theory. Also, a real-time identification algorithm relating to the radiation coefficient of a furnace chamber in this model has been presented, and computer simulation for this model has been performed with satisfying result: the error between the computed temperature and the real temperature of a slab being output from a reheating furnace is less than 0.05 degree centigrade.