With the development of the social economy, people’s demand for energy is increasing. As a kind of high energy consumption equipment in petrochemical enterprises, the heating furnace is imperative to reduce its energy consumption. Therefore, in order to further improve the thermal efficiency of the heating furnace and reduce the emission of pollutants, this paper combines the actual operation of the SRT-III heating furnace in the chemical plant to establish a fluid domain model. The effects of different values of excess air coefficient, air preheating temperature, and oxygen concentration on the flow field characteristics and furnace thermal efficiency under two kinds of blackness were analyzed by numerical simulation. The results show that higher blackness has higher furnace thermal efficiency. Under the conditions of a balance between thermal efficiency and environmental protection performance, the optimal values of excess air coefficient, air preheating temperature, and oxygen concentration are 1.20, 473 K, and 25%, respectively.