There are lots of physical changes and chemical reactions in the processes of iron and steel making, these processes are quite complex in the aspect of heat transfer.The processes of iron and steel making can be approximately divided into three kinds.The first kinds are the processes of fusion metallurgy which involve enormous chemical reactions,such as blast furnace,converter,electric furnace and coke oven.The second kinds are the processes of heating and cooling which are mainly the physical changes,such as walking-beam reheating furnace,annular heating furnace and car-type furnace.The third kinds are the processes of heat treatment which mainly adjust metallurgical structure of metal,such as roller hearth heat treatment furnace, strip continuous heat treatment vertical/horizontal furnace and HPH bell-type annealing furnace.Every process can only be finished in particular thermal equipment.And all the physical and chemical processes mentioned above must obey first principles of engineering thermodynamics,heat & mass transfer,hydromechanics, combustion,metallurgy physical chemistry etc,and which can be summarized as principle of heat transfer,mass transfer,momentum transfer and chemistry reaction.In this paper,based on first principle of heat and mass transfer in iron and steel making processes,a series of mathematical models of thermal equipments and processes are presented.Such as the model of hot-blast stoves,coke oven,CDQ-boiler system,sintering, reheating furnace,soaking furnace,annular heating furnace,roller hearth heat treatment furnace,strip continuous heat treatment vertical/horizontal furnace,HPH bell-type annealing furnace,control cooling of medium plate,burner,heat exchanger and regenerative burner etc.The on-line application of the model is based on experimental certification of the mathematical model.And finally the computer optimization system of metallurgical thermal process is obtained. There are lots of physical changes and chemical reactions in the processes of iron and steel making, these processes are quite complex in the aspect of heat transfer. The processes of iron and steel making can be divided into three kinds.The first kinds are the processes of fusion metallurgy which involve enormous chemical reactions, such as blast furnace, converter, electric furnace and coke oven. the second kinds are the processes of heating and cooling which are mainly the physical changes, such as walking-beam reheating furnace, annular heating furnace and car-type furnace.The third kinds are the processes of heat treatment which mainly adjust metallurgical structure of metal, such as roller hearth heat treatment furnace, strip continuous heat treatment vertical / horizontal furnace and HPH bell-type annealing furnace. can only be finished in particular thermal equipment. And all the physical and chemical processes mentioned above must obey first principles of engin eering thermodynamics, heat & mass transfer, hydromechanics, combustion, metallurgy physical chemistry etc, and which can summarized as principle of heat transfer, mass transfer, momentum transfer and chemistry reaction. In this paper, based on first principle of heat and mass transfer in iron and steel making processes, a series of mathematical models of thermal equipments and processes are presented. Asch model of hot-blast stoves, coke oven, CDQ-boiler system, sintering, reheating furnace, soaking furnace, annular heating furnace, roller hearth heat treatment furnace, strip continuous heat treatment vertical / horizontal furnace, HPH bell-type annealing furnace, control cooling of medium plate, burner, heat exchanger and regenerative burner etc. The on-line application of the model is based on experimental certification of the mathematical model. And finally finally the computer optimization system of metallurgical thermal process is obtained.