<p>Hydrogel-based self-floating catalytic materials have become a key interfacial platform in the field of solar-driven chemistry, effectively solving the difficulties of traditional powder catalysts in the aqueous phase, such as easy agglomeration, sedimentation, and limited mass transfer. In this study, the design strategy, structural properties, and interfacial advantages of these materials were systematically described, and the mechanisms of precursor mixing, <i>in situ</i> synthesis, and post-modification in regulating the distribution of active sites, gel structure formation, and multifunctional integration were analyzed. Through the construction of stable three-phase interfaces, the materials form a reaction microenvironment with a generalized enhancement effect. The structural design significantly improves the light trapping efficiency and carrier separation performance in photocatalytic processes and simultaneously strengthens the mass transfer process and local reactant concentration in peroxide activation reactions, establishing a synergistic system in which the adsorption, enrichment, and catalytic processes are tightly coupled. Successful applications in the fields of organic pollutant degradation, solar-driven chemical synthesis, and interfacial evaporation have demonstrated the wide applicability of this technology. By systematically combining the research progress in this field, this study aims to provide a theoretical basis for the development of efficient and stable interfacial catalytic platforms and promote the development of sustainable environmental remediation and energy conversion technologies.</p>