Coal fly ash, as a bulk aluminosilicate solid waste, poses environmental risks due to the migration of harmful elements during its placement and resource utilization. This paper reviews the occurrence state of harmful elements in coal fly ash, the migration of these elements during placement and utilization, influencing factors, and methods for environmental risk assessment. The majority of harmful elements in coal fly ash primarily exist in residual or iron-manganese oxide states. During the placement process, the migration of harmful elements in coal fly ash is influenced by factors such as the geochemical properties of elements, particle size, and pH value, exhibiting different characteristics. In the process of resource utilization, harmful elements also show different migration rules. During the process of soil improvement using coal fly ash, the migration of harmful elements to the surface or deep soil layers varies due to their different properties, but there is a tendency for migration to the surface soil over time. In the preparation of functional materials based on coal fly ash, metal harmful elements mainly migrate into the product, while non-metal harmful elements primarily migrate into the waste liquid. In the extraction process of valuable elements from coal fly ash, harmful elements migrate into waste liquid, waste residue, and products, but specific details are currently lacking. Finally, this paper summarizes existing standards and regulations related to the environmental risk of harmful elements in coal fly ash, as well as environmental risk assessment methods, analyzes existing problems, and proposes research prospects.