Abstract: Steel slag is the main solid waste produced by metallurgical enterprises. Its high output and low utilization rate have caused significant harm to the ecological environment. Poor volume stability is the primary factor hindering the large-scale application of steel slag. This paper focuses on the volume expansion characteristics of steel slag and analyzes research progress on volume stability control from multiple dimensions. The results show that both tempering methods and process methods can significantly reduce the content of active substances in molten steel slag and effectively regulate its volume stability. Cooled solid steel slag is mainly utilized in two forms: steel slag aggregate (SSA) and steel slag powder (SSP). Key methods for controlling SSA volume stability include aging treatment, carbonization treatment, and surface modification. Among these, aging is currently the primary method. However, natural aging requires a long period and lacks uniformity. This process can be significantly shortened by applying external conditions such as temperature, pressure, and humidity, though this leads to disadvantages such as high wastewater treatment demands, elevated energy consumption, and reduced SSA quality. The pH value fluctuation method was applied to both direct and indirect carbonization treatments. Direct carbonization efficiency can be improved by optimizing temperature, pressure, CO₂ concentration, and catalysts, thereby reducing SSA expansion risk. Surface modification is classified into inorganic and organic modification methods, both of which significantly reduce volume expansion risk. However, acid treatment generates waste liquids that are difficult to manage, and organic modification suffers from limitations such as poor film formation, high elasticity, and brittleness. For SSP, primary control methods include grinding, carbonization, surface modification, and combined treatments. Grinding reduces particle size, thereby enhancing hydration activity and reducing volume expansion risk. SSP carbonization methods are diverse; beyond direct carbonization, indirect methods such as pH adjustment or microbial treatments induce alkali metal ion precipitation, achieving high carbonization efficiency without reliance on traditional equipment. Though complex, these methods do not require strict external conditions. Microbial carbonization, in particular, reaches efficiencies of 90%–95%. Surface modification of SSP is also divided into inorganic and organic methods, with acid treatment being the main organic approach. Post-treatment, SSP exhibits increased specific surface area, hydration activity, and volume stability. Combining treatment methods yields better results; among them, carbonization paired with acid treatment, alkali activation, or artificial aggregate preparation further enhances SSP volume stability compared to single treatments. Concrete made from artificial steel slag aggregate demonstrates excellent performance, mitigates the shortage of natural aggregates, and holds promising potential for research and practical applications.