As Fe oxide minerals such as magnetite and hematite are the main Fe-bearing minerals in iron ore deposits, their oxygen isotope geochemistry has great potentials in tracing the genesis of iron ore deposits. In this paper, based on the summarization of the basic principles of oxygen isotope fractionation in Fe oxide minerals and the general processes related to iron mineralization, the authors calculated oxygen isotope distributions of Fe oxide minerals in different types of iron ores, and the results were compared with the data previously obtained from various iron ores. Then a case study was carried out on submarine volcanic-hosted iron ore deposits from Zhibo, Chagangnuoer, and Beizhan iron ore deposits in Xinjiang for their oxygen isotope compositions of magnetite. The results show that the magnetite of these deposits have δ¹⁸O_SMOW mainly between 1‰ and 3‰, indicating that their formation was mainly controlled by high-temperature magmatic or magmatic-hydrothermal processes, with the late-stage low-temperature alteration having little effect on the iron mineralization.