The Xiaohongshilazi Pb-Zn (Ag) deposit is a representative medium-sized deposit within the Jizhong-Yanbian copper-nickel polymetallic metallogenic belt, the main views for deposit types mainly include VMS type, medium-low temperature hydrothermal vein type, and exhalative deposits overprinted by hydrothermal fluid. In order to constrain the ore genesis, the Fe isotope characteristics of pyrite and pyrrhotite are systematically investigated. The overall δ56Fe values range from –0.82‰ to 1.00‰; Compared with other various type deposits, we have found that the Xiaohongshilazi Pb-Zn (Ag) deposit shows the characteristics of both hydrothermal and sedimentary deposits, hence the metallogenic hydrothermal fluid should be hot spring, and MVT type is most suitable. The δ56Fe values of pyrite gradually decrease from stage 1 (1.00‰) through stage 2 (0.21‰ ~ 0.83‰) to stage 3 (0.08‰ ~ 0.12‰); in comparison, the δ56Fe values of pyrrhotite gradually increase from stage 1 (–0.82‰) through stage 2 (–0.55‰ ~ 0.13‰) to stage 3 (–0.23‰ ~ –0.21‰), which is the typical Rayleigh fractionation characteristics. Within coexisting mineral pairs, the pyrrhotite is preferentially enriched in light Fe isotopes relative to pyrite, which is the same with previous studies. In addition, a Fe isotope fractionation model has also been established, which imply that the collected samples were correspond to the intermediate period (33.96% ~ 63.70%) of the whole mineralization process, while 63.59% of the metal resources related to the early period (0.00% ~ 33.96%) and late period (63.70%~ 100.00%) have not been discovered. In summary, the Fe isotopic compositions is mainly controlled by Rayleigh process, although the Fe isotopic evidence supported the MVT genesis, the geological characteristics are slightly different hence it should be classified as an MVT-like deposit; and there is still further prospecting potential within orefield.