Abstract: The progressive development of the steel industry has led to annually increase in the accumulation of steel slag, not only occupying large tracts of land but posing certain hazards to the ecological environment. It is very important to make the harmless treatment and resource utilization of steel slag. Driven by the principle that lucid waters and lush mountains are invaluable assets, research of the resource recovery of steel slag has emerged as a significant topic within the realm of sustainable development, achieving tangible progress across diverse sectors. Characterization of steel slag by techniques including X-ray diffraction（XRD） and scanning electron microscope（SEM） reveals its high cementitious properties and elevated contents of valuable metallic elements such as Fe. Steel slag can not only serve as a high-value-added cementitious material but also facilitate the extraction of valuable metals to achieve its multi-dimensional utilization. However, inherent limitations of steel slag, such as the presence of RO phase, which impairs its cementitious properties and grindability, restrict its large-scale utilization. Furthermore, most iron in steel slag exists in the form of FeO enriched in the RO phase or non-magnetic ferrites, which increases the difficulty of extracting iron. This paper comprehensively reviewed the current status of comprehensive utilization of steel slag in the fields of ceramic materials, functional fillers, and construction materials in recent years domestically and internationally, and analyzed the main factors restricting the application of steel slag in these fields. Based on the practical application, this paper proposes that the utilization of steel slag should evolve towards a multi-dimensional and wide-ranging direction. In addition, by analyzing the characteristics and technical advantages of wet processing technology and pyrometallurgical processing technologies, including oxidation, reduction, and reconstruction methods, for separating iron from the RO phase of steel slag, the bottlenecks encountered by different processes in practical application were introduced, and provided an outlook on the future iron extraction technology from steel slag in response to the existing problems. The result will provide references for the resource utilization of steel slag and iron extraction from the RO phase.