Phosphorus (P) is one of the most deleterious elements in iron ore, it is easy to form iron phosphides that make steel brittle during reduction processes. A new process (direct reduction and flash smelting separation (FSS)) of treating high phosphorus iron ore (HPIO) is introduced in this paper. By limiting the smelting separation between slag and iron to the level of about 1 s, the reduction and migration process of P element was restrained, and the content of P element in the metallic iron obtained after separation was limited to about 0.3 wt%. The effects of flash smelting temperature and ore particle size on the flash smelting process were studied. The migration process of phosphorus was analyzed, and a mathematical model of this smelting process was established to facilitate the visualized understanding and regulation of this process. (C) 2020 Elsevier B.V. All rights reserved.