<p>Serpentinization is widely developed in the deep ocean and represents a major source of hydrogen generation and accumulation in the ocean floor. However, the distribution, exploration, and development of submarine hydrogen resources remain at an early stage. A key challenge lies in the effective identification of hydrogen-bearing systems. Magnetite, a secondary mineral formed during serpentinization, is produced synchronously with hydrogen and may therefore serve as a useful proxy for hydrogen generation. In this study, we systematically investigate the magnetic properties of magnetite formed during serpentinization and evaluate their implications for submarine hydrogen exploration. The results indicate that magnetite content is primarily controlled by reaction temperature and the progression of serpentinization. At advanced stages, magnetite abundance can be used as an indicator of hydrogen production. However, significant variability exists among different tectonic settings. Serpentinites from slow- and ultra-slow-spreading mid-ocean ridges contain substantially higher magnetite contents than those from subduction zones and ocean-continent transition zones, suggesting a greater potential for hydrogen generation in ridge environments. Furthermore, magnetite formed during serpentinization can acquire remanent magnetization aligned with the geomagnetic field, thereby significantly influencing the amplitude and morphology of marine magnetic anomalies. High-amplitude anomalies and characteristic skewness may provide geophysical constraints for identifying the serpentinized zones, which are potential sites of hydrogen accumulation. Therefore, high-resolution seafloor magnetic surveys, combined with rock magnetic analyses, provide an effective approach for delineating submarine hydrogen resources.</p>