Abstract: Microbially induced calcium carbonate precipitation (MICP) is a novel environmentally friendly treatment technology, which shows broad prospects in solid waste treatment and utilization due to its unique mineralization and bio-enzymatic catalysis mechanism. Based on the hydration characteristics of steel slag, this paper explores the influence of carbonation conditions and enzymatic characteristics on carbonate nucleation, analyzes and summarizes the research progress on the reaction mechanism of MICP and carbonation, phase evolution of steel slag in bio-carbonation modification, carbonate nucleation, and crystal growth. Furthermore, from the perspectives of mechanical properties, hydration heat, and volume stability, the impact mechanism of modified steel slag on the hydration characteristics of cement-based cementitious materials is further reviewed. The paper points out the current deficiencies in microorganism-carbonation technology in the research of steel slag modification, providing valuable references for achieving low-pollution and high-quality utilization of steel slag.