Abstract: The Nantuozi Iron Deposit in eastern Hebei is hosted in the Yangshan Formation of the Neoarchean Luanxian Complex and constitutes a typical Algoma-type Banded Iron Formation (BIF) deposit in the North China Craton. We investigated ore samples from drill cores using petrographic observation, whole-rock major- and trace-element analysis, and iron isotope testing to decipher its geochemical characteristics, the source of ore-forming materials, the paleo-sedimentary environment, and evidence of late hydrothermal reworking. The results show that the ores mainly consist of magnetite and quartz, associated with gangue minerals such as plagioclase, biotite, and hornblende; accessory minerals, including calcite and pyrite, occur locally. Terrigenous clastic components are extremely low, demonstrating that the ores are typical chemical precipitates. After rare earth element (REE) normalization to Post-Archean Australian Shale (PAAS), all samples show right-inclined REE patterns with light REE depletion and heavy REE enrichment, along with positive La, Eu, and Y anomalies and insignificant negative Ce anomalies. All (La/Yb)_N ratios are less than 1, and Y/Ho ratios are generally close to the seawater endmember, indicating that ore-forming fluids were dominated by seawater with a small amount of mixed submarine high-temperature hydrothermal fluids. All iron isotope δ⁵⁶Fe values are positive. Combined with the lack of obvious negative Ce anomalies, we infer that the deposit formed in a generally anoxic marine environment, and that iron materials underwent partial oxidation during mineralization. Together with the regional geological setting and geochemical signatures, mineralization of high-grade iron ore at the Nantuozi Deposit was controlled by both sedimentary metamorphism and hydrothermal activity, and its metallogenic mechanism is highly consistent with the “remobilization and re-enrichment of iron” model. This study provides geochemical references for research on metallogenic regularities in Neoarchean BIFs and regional prospecting in the Luanxian-Luannan ore concentration area, eastern Hebei Province.