Abstract: Soil heavy metal pollution has emerged as a critical environmental issue that threatens the safe utilization of land resources and the sustainable development of agriculture. The combined remediation technology of mineralizing microorganisms and biochar, as a green and efficient strategy for heavy metal pollution control, has attracted much attention in recent years. However, the intrinsic mechanism of their synergistic effect and the multi-factor interaction relationship have not yet been systematically clarified. This review, based on bibliometric analysis, summarizes the individual and combined mechanisms of mineralizing microorganisms and biochar in the immobilization of soil heavy metals. Emphasis is placed on analyzing the transformation pathways of heavy metal speciation, the regulatory effects on the soil microenvironment, and key influencing factors, while also evaluating the practical application potential and the challenges faced. The literature indicates that mineralizing microorganisms primarily facilitate the conversion of heavy metals into more stable forms through processes such as biomineralization, extracellular complexation, and biotransformation. Biochar, owing to its high specific surface area, abundant functional groups, and porous structure, enables efficient adsorption and fixation of heavy metals while simultaneously improving soil physicochemical properties. The synergy between the two significantly promotes the transformation of heavy metals from available forms to residual and organically bound fractions, enhances the capacity for regulating soil pH and redox potential, increases microbial metabolic activity and colonization efficiency, and yields a remediation performance markedly superior to that of individual treatments. This synergistic effect is jointly influenced by multiple factors such as the characteristics of biochar, the metabolic activity of microorganisms, the types and forms of heavy metals, and soil environmental conditions. At present, this combined technology has been applied in the demonstration of farmland and complex contaminated site remediation, which can reduce the heavy metal content in crops by more than half. However, challenges remain, including limited environmental adaptability, high costs for large-scale application, and uncertain long-term stability. Future research should focus on the targeted construction of functional strains and modified biochar, deepen the analysis of microscopic molecular mechanisms, promote the establishment of multi-technology integration and standardized application systems, and provide a theoretical basis and technical solutions for the efficient and green remediation of soil heavy metal pollution.