High-temperature iron-containing kiln slag is a by-product of metallurgical dust after zinc extraction treatment by rotary kiln,because of its high impurity content and difficult to use effectively,resulting in low added value of products and waste of iron-containing resources. In view of such characteristics as high iron grade,high metallization rate and high slag discharge temperature,an online reduction fusion process of high-temperature iron-containing kiln slag is proposed,and the effects of reducing fusion temperature,carbon mixing amount,constant temperature time,and slag additives (binary alkalinity,magnesium-to-aluminum ratio) on fusion effect and iron recovery are systematically studied. The results show that the appropriate reduction temperature and carbon distribution could promote the full reduction of iron oxides and the aggregation of iron droplets. When the temperature is increased from 1 400 ℃ to 1 500 ℃,the iron recovery rate is increased from ineffective separation to 84. 41%. When the carbon mixing amount is increased from 10. 37 g to 27. 63 g, the iron recovery rate is increased from 36. 84% to 90. 93%. Optimizing the slag alkalinity and magnesium-aluminum ratio alkalinity and magnesium-aluminum ratio is conducive to improving the iron recovery,but if the two continue to increase, high melting point phases and magnesium-aluminum spinel will be generated,which will worsen the slag-iron separation effect and lead to a decrease in iron recovery. Under the optimized conditions of reducing fusion temperature of 1 500 ℃, carbon mixing amount of 27. 63 g,constant temperature time of 40 min,binary alkalinity of 1. 5,and magnesium-aluminum ratio of 0. 6,the iron recovery rate could reach 95. 92%,and the iron grade in the obtained iron-containing materials is 97. 16%. This process can realize the efficient separation of slag and iron and the high-value recovery of iron resources,and at the same time make full use of the sensible heat of kiln slag to avoid cooling energy consumption and iron loss in the traditional beneficiation process,providing a new idea for the green and low-carbon treatment of metallurgical solid waste.