The flue gas treatment system is the most important part of the rotary hearth furnace process, and the waste heat boiler is the core equipment of the flue gas treatment system. The characteristics of the flue gas of rotary hearth furnace were analyzed, and the process flow and process parameters of the waste heat utilization system of the flue gas in a steel plant were emphatically introduced. The causes of blockage of flue gas system and corrosion of boiler tubes were analyzed. Based on the practice, the measures to prevent blockage and corrosion of flue gas utilization system were put forward, and the antisepsis of the waste heat boiler was explored. Through the implementation of these measures, the blockage and corrosion of flue gas system were alleviated, which had been verified in the actual production of rotary hearth furnace. It provided a useful reference for solving the blockage and corrosion of the waste heat utilization system of the rotary hearth furnace.