The Nanfen iron deposit is the largest open-pit iron deposit not only in China but also in Asia. Since 1949, it has become the main mine to provide high grade iron for the Benxi Steel Iron Cooperation. This paper discusses the geological background of the mineralization the geological characteristics and the major and rare earth elements in the Nanfen iron deposit. The major and rare earth elements (REE) of banded iron formations are analyzed and it is shown that the average bulk compositions of banded oron formations (BIF) are rich in Fe and SiO₂, but with very low Al₂O₃ and TiO₂ contents, as consistent with the characteristics in Anshan-Benxi, Wutaishan and Qianshan. These chemical features show that they are chemical sediments of detrital input, with very low REE concentrations, with the shale-normalized REE patterns of distinct positive anomalies of Eu and the depletion of light REE relative to heavy REE. This demonstrates that the BIFs are the products of chemical sedimentions from the paleo-seawater with significant input of volcanic hydrothermal fluids.