Abstract: Multi-source coal-based solid wastes—such as coal gangue, fly ash, and coal gasification slag—represent the primary solid byproducts generated during coal mining, processing, and utilization, with enormous production volumes. The resource-oriented utilization and environmental risk control of these wastes have emerged as key research priorities in the fields of environmental science and resource utilization. The massive accumulation of coal-based solid waste is a common concern in coal mines around the world, and the disposal of coal-based solid waste has become an important factor affecting resource development and environmental protection. The application of coal-based solid waste to soil remediation is one of the important directions for the combination of coal-based solid waste disposal and ecological civilization construction. In order to achieve the dual goals of resource utilization and soil remediation of multi-source coal-based solid wastes, this paper introduces the types, physicochemical properties and utilization modes of multi-source coal-based solid wastes, such as fly ash, coal gangue and coal gasification slag, focuses on the current research status of multi-source coal-based solid wastes as soil conditioners applied to soil water retention and fertilizer retention, and summarizes the progress of research on the effects and mechanisms of heavy metal remediation using multi-source coal-based solid wastes as heavy metal passivators, and points out the technical challenges facing the application of multi-source coal-based solid wastes to soil remediation. It also points out the technical challenges of applying multi-source coal-based solid waste to soil remediation, and discusses the key research directions of applying multi-source coal-based solid waste to soil remediation. However, heavy metals contained in coal-based solid wastes can migrate into the soil environment via leaching, potentially inducing secondary contamination. The evaluation of heavy metal leaching toxicity thus constitutes a pivotal component of risk control. Future research should focus on optimizing the activation and modification processes of coal-based solid wastes, elucidating the migration and transformation mechanisms of heavy metals in soil, and establishing a precise risk assessment framework. Meanwhile, synergistic remediation technologies utilizing multi-source solid wastes should be explored to achieve the dual objectives of waste resource utilization and soil environmental management. These efforts aim to provide scientific support for the theoretical and technological research on the high-value development and utilization of multi-source coal-based solid wastes as potential resources.