The South Narimalahei area is located on the north side of the Middle Kunlun fault in the eastern section of the East Kunlun composite orogenic belt． The ore body is veined and controlled by structures and secondary fissures，which occurs in the structural alteration fracture zone in the Late Triassic granodiorite． In this deposit，copper mineralization is closely related to silicification and sericification． The formation process of the deposit includes hydrothermal mineralization and supergene oxidation． In this paper，the fluid inclusion mineralogy，microscopic temperature measurement and stable isotope studies have been carried out for ore of the main mineralization stage． The results show that the primary gas-liquid two-phase inclusions and a small amount of single-liquid inclusions are mainly developed in the quartz in the main mineralization stage． The results of microscopic temperature measurement show that the ore-forming fluid which has low temperature ( 151． 7℃-- 205． 8℃) ，low salinity( 2． 06wt%--4． 94wt% NaCl) ，low density ( 0． 86--0． 92 g /cm3 ) and shallow formation( 1． 5--3． 0 km) is a hydrothermal solution of NaCl-H2O system． Hydrogen and oxygen isotope results show that the ore-forming fluids mainly come from atmospheric precipitation，with a small amount of magmatic fluids participating．It is preliminarily determined that the South Narimalahei copper polymetallic deposit is a lowtemperature hydrothermal vein deposit．