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The Wulasigou Cu-Pb-Zn deposit, located 15km northwest of Altay city in Xinjiang, is one of many Cu-Pb-Zn polymetallic deposits in the Devonian Kelan volcanic-sedimentary basin in southern Altaids. Two mineralizing periods can be distinguished: the marine volcanic sedimentary Pb-Zn mineralization period, and the metamorphic hydrothermal Cu mineralization period, which is further divided into an early bedded foliated quartz vein stage (Q1) and a late sulfide-quartz vein stage (Q2) crosscutting the foliation. Four types of fluid inclusions were recognized in the Q1 and Q2 quartz from the east orebodies of the Wulasigou deposit: H2O-CO2 inclusions, carbonic fluid inclusions, aqueous fluid inclusions, and daughter mineral-bearing fluid inclusions. Microthermometric studies show that solid CO2 melting temperatures ( Tm,co2) of H2O-CO2 inclusions in Q1 are from −62.3°C to −58.5°C, clathrate melting temperatures ( Tm,clath) are from 0.5°C to 7.5°C, partial homogenization temperatures ( Th,co2) vary from 3.3°C to 25.9°C (to liquid), and the total homogenization temperatures ( Th,tot) vary from 285°C to 378°C, with the salinities being 4.9%-15.1% NaCl eqv. and the CO2-phase densities being 0.50-0.86 g/cm3. H2O-CO2 inclusions in Q2 have Tm,c02 from −61.9°C to −56.9°C, Tm,clath from 1.3°C to 9.5°C, Th,co2 from 3.4°C to 28.7°C (to liquid), and Th,tot from 242°C to 388°C, with the salinities being 1.0%-15.5% NaCl eqv. and the CO2-phase densities being 0.48-0.89 g/cm3. The minimum trapping pressures of fluid inclusions in Q1 and Q2 are estimated to be 260-360 MPa and 180-370 MPa, respectively. The δ34S values of pyrite from the volcanic sedimentary period vary from 2.3‰ to 2.8‰ (CDT), and those from the sulfide-quartz veins fall in a narrow range of −1.9‰ to 2.6‰ (CDT). The δD values of fluid inclusions in Q2 range from −121.0‰ to −100.8‰ (SMOW), and the δ18OH2O values calculated from δ18O of quartz range from −0.2‰ to 8.3‰ (SMOW). The δD- δ18OH2O data are close to the magmatic and metamorphic fields. The fluid inclusion and stable isotope data documented in this study indicate that the vein-type copper mineralization in the Wulasigou Pb-Zn-Cu deposit took place in an orogenic-metamorphic enviroment. [ABSTRACT FROM AUTHOR]