Smelting process requires the off-gases to be cooled, filtered, cleaned and exhausted in environmental compliance. Waste-heat boiler (WHB) is the heat recovery equipment directly connected with the smelting furnace outlet, which is working in a tough condition, leading to easy-fouling, easy-abrasion and easy-corrosion. The optimized design of WHB is key to ensure the smelting process safety and energy saving. Based on the composition test of the dust and a large amount of engineering experience, an optimized hood of WHB for the bottom-blow smelting furnace is presented. The air leakage is controlled in a reasonable range. The slagging problem and low-temperature corrosion near the furnace outlet are solved. The working rate of the smelting system is increased. It makes the metallurgical industry developing in a green and efficient way.