Nowadays, various kind of reactor furnaces are widely used for the production in industry. The raw materials charged into the furnace generate reaction heat produced by blowing gas. Generally speaking, the reaction heat generated in the furnace is remarkably high. Therefore the occurrence of an inappropriate temperature distribution in the furnace may make damege or serious accident of the furnace. This is the motivation of furnace control. The author is considering the application of studied results to the furnace control of Blast Furnace in steel industry. To the propose, the approximated and simplified Macro Model of the Blast Furnace is constructed which has the function of representation of qualitative characteristics of the furnace in dynamical sense. The furnace temperature, distribution greatly effects both on the producting and the product quality of the furnace. Needless to say, stable furnace operation is indispensable for the economical prosperity of the industry. In this paper, macro simulation of the furnace is developed to support the analysis and design of the furnace control. Using the simulator, the stability and the control characteristics for inner furnace temperature distribtion are analised quantitatively.