<p>Metallothermic reduction reaction (MRR) is a pivotal high-temperature reduction technique extensively employed in the preparation of high-purity metals, alloys, and certain functional non-metallic materials. While a substantial body of literature has explored reductant selection and product morphology in MRR processes, systematic investigations into how precursor types influence the reaction pathways, by-product behavior, and interfacial evolution mechanisms remain limited. This review adopts the framework of “precursor structure-reaction mechanism-diagnostic methodology” to comprehensively summarize the thermodynamic characteristics, interfacial coupling behaviors, and by-product evolution pathways of four major precursor systems—oxides, halides, sulfides, and nitrides—within MRR reactions. The multi-scale interactions and reaction-specific features of these systems are elucidated in detail. Furthermore, the review compares a wide range of mechanistic elucidation techniques, from classical thermal analysis to synchrotron-based in situ imaging and interfacial multiphysics diagnostics, highlighting their respective advantages in terms of temporal resolution, spatial mapping, and structural tracking of structural evolution. It is proposed that future MRR research should transition from a “reductant-centered” to a “system-centered” paradigm, through leveraging precursor structure design and integrated multi-technique characterization to establish new strategies for green metallurgy and the fabrication of high-performance functional materials.</p> Graphical abstract <p></p>