Abstract: Fly ash is rich in aluminosilicate phases, metal oxides, calcium-bearing components, and residual carbon, which collectively provide the compositional basis for its use as an aluminosilicate precursor, a source of catalytic activity, and a low-cost catalyst support. These characteristics offer opportunities to extend fly ash utilization beyond conventional construction materials toward value-added catalytic applications. This review examines the compositional characteristics, activation methods, catalytic material categories, and major applications of fly ash-based catalytic materials. Particular attention is given to the effects of physical and chemical activation on particle structure, aluminosilicate reactivity, surface acid-base properties, and the exposure of metal-containing species. The formation pathways and functional characteristics of native, supported, and derived fly ash-based catalytic materials are systematically summarized, together with their reaction mechanisms and applicability in CO2 capture and conversion, pollution control, and catalytic conversion of carbon-based resources. The available evidence indicates that catalytic performance is jointly governed by aluminosilicate reactivity, the dispersion and oxidation states of metal species, acid-base and redox sites, and pore structure and mass transfer. Further development toward large-scale application requires greater attention to source classification and feedstock standardization, quantitative characterization of active sites, long-term structural stability, and component leaching. By clarifying the relationships among fly ash characteristics, activation routes, material types, and reaction requirements, this review provides a basis for the targeted preparation, application matching, and engineering assessment of fly ash-based catalytic materials. It also offers insights into the integration of high-value utilization of coal combustion solid wastes with pollution control and broadens the potential role of fly ash valorization in synergistic pollution and carbon reduction.