<p>In recent years, room-temperature gallium-based liquid metals (Ga-based LMs) have rapidly advanced in fields such as flexible electronics, soft robotics, micro/nanofabrication, and biomedicine, owing to their combination of high electrical/thermal conductivity and fluidic plasticity. Despite the surge of related studies, systematic clarification of how and why LM particles deform at the micro/nanoscale remains limited. Insights derived from the macroscale cannot be directly extrapolated to micro/nano dimensions, where identical stimuli (e.g., heating, acid treatment, or template confinement) often induce new phase formation and irreversible morphological locking. Typical outcomes include the generation of α-GaOOH and β-Ga₂O₃, core-shell reconstruction, and shape fixation. To address this gap, this review systematically summarizes the evolutionary modes of Ga-based LM micro/nanoparticles. Using “whether new phases emerge” and “whether the deformation is reversible” as criteria, these modes are classified into two categories: physical deformation and interfacial chemical reconstruction. Furthermore, the distinctions between the application scenarios associated with each mechanism are clarified. This review aims to provide practical guidelines for the design and fabrication of LM micro/nanomaterials, while establishing a unified classification and reference for the development of the mechanism and the application.</p>