The Angouran Zn-Pb-Ag deposit, the biggest Zn-Pb mine in Iran, is situated in the northwestern Sanandaj-Sirjan metamorphic zone of the Zagros orogen, and hosted by the Neoproterozoic-Cambrian marble-micaschist sequence. The orebodies occur in a pipe-shaped body within the marble, which are downwards changed into stratiform or stratoid orebodies in the contact between the marble and the underlying micaschist. Massive or brecciated carbonate ore, mixed sulfide and carbonate ore, and sulfide ore sequentially occur in the shallow to deep parts relative to the current surface. The sulfides consist of sphalerite and subordinate galena, including the early stage of Fe-rich sphalerite and the late stage of Fe-poor sphalerite. The carbonate ore comprises hypogene and supergene smithsonite and calcite. Fluid inclusion data demonstrate that the ore-forming fluid in the sulfide stage is characterized by a Na+-Ca2+-Cl--SO2+4 brine system with low temperature and high salinity, which may originate from highly evaporative brine. The characteristics of C-O, S and Pb isotope indicate that the ore-forming fluid have strongly interacted with the host marble; Sulfur in the sulfides is a result of thermal-chemical sulfate reduction; Metals is derived from crust. In summary, the Angouran deposit is characteristic of absence of igneous intrusions, epigenetic mineralization, brecciated carbonate-hosted ore, and the ore-forming fluid being basinal brine origin. This indicates that the deposit is similar to classical Mississippi valley-type (MVT) deposit but clearly distinct from VMS, SEDEX, and intrusion-related hydrothermal deposits. The hypogene smithsonite at Angouran is probably related to Neogene-Quaternary volcanic activity, which overprinted the sulfide mineralization. The supergene smithsonite is the result of the oxidation of the sulfide ores under a surface environment.