Abstract: Fe(-Si) (oxyhydr)oxides are significant constituents in submarine hydrothermal systems, serving as an important carrier in geological, environmental, and biological information. Fe(-Si) (oxyhydr)oxides have three formation mechanisms: the direct oxidation of primary sulfides, the precipitation from low-temperature hydrothermal fluids, and microbial-mediated mineralization. Fe (oxyhydr)oxides formed by the oxidation of sulfides have typical chemical structures. It is composed of mainly goethite, minor hematite, lepidocrocite, ferrihydrite, schwertmannite, and natrojarosite. The formation of Fe (oxyhydr)oxide is generally dependent on the oxidation-hydrolysis-precipitation of sulfides or solid-state transformation of precursor materials. Minerals precipitated by the low-temperature hydrothermal fluids, mainly include opal-A, Si-ferrihydrite, and nontronite. Temperature is the most important factor controlling the precipitation of these minerals. As the temperature dropping, the sequence of mineral precipitation transitions from opal-A to Si-ferrihydrite and nontronite. It is noteworthy that a large number of ultrastructures with unique morphologies and compositions are present on the accumulation of Fe(-Si) (oxyhydr)oxides, including sheaths, stalks, and twisted stalks. They are Fe oxide crusts formed by Leptothrix ochracea, Mariprofundus ferrooxidans, and Gallionella ferroginea during the life activities. This study comprehensively summarized the origin and formation mechanism of Fe(-Si) (oxyhydr)oxides in submarine hydrothermal systems, and provided clues for understanding the evolution of weathering residual gossan and the diagenesis of banded iron formation.