Abstract: Arsenopyrite (FeAsS) is a typical arsenic−containing mineral, and its oxidation process is complex and of great significance to environmental protection and resource utilization. Hydrometallurgy is an effective method to oxidize the mineral structure of arsenic pyrite and lead to the transformation of arsenic species. This review systematically summarizes the phase transformation mechanisms of arsenopyrite and arsenic species evolution patterns under various hydrometallurgical oxidation systems, including atmospheric pressure oxidation system, pressure oxidation, bio−oxidation, and other advanced oxidation techniques. In chemical oxidation systems, arsenic predominantly undergoes sequential oxidation from As(Ⅲ) to As(Ⅴ) species. Under pressure oxidation systems, increasing temperature and pressure can effectively improve the leaching rate of arsenic and promote the transformation of arsenic to arsenate. Bio−oxidation demonstrates remarkable improvement in arsenopyrite dissolution through targeted regulation of microbial species composition, synergistic interactions within microbial communities, and optimization of microenvironments. Alternative oxidation strategies achieve enhanced oxidation efficiency by modifying mineral microstructure or surface properties, thereby promoting phase transformation. The three systems have their own advantages and disadvantages. At the same time, this paper puts forward the future research and development direction, which can provide theoretical reference for strengthening the efficient oxidation and green production of arsenopyrite.