The Dadonggou lead-zinc ore deposit is one of the massive sulfide deposits in the Devonian Kelan volcanic-sedimentary basin on the southern margin of the Altay Mountains. Controlled by regional Abagong-Kurti fault, the ore bodies occur in layers in the second lithologic unit of Upper Kangbutiebao Formation which consists of calcareous sandstones，biotite schists and chlorite schists．The ore minerals are sphalerite, galena and pyrite assuming massive, disseminated, banded and veinlet forms. During the regional tectonic-hydrothermal metamorphism of Carboniferous-Permian orogeny, this ore deposit experienced hydrothermal transformation, resulting in the development of veinlike quartz and mineralization. Two metallogenic stages can be identified: the first was the marine volcanic sedimentary stage, and the second was the metamorphic hydrothermal stage. There are two periods of quartz veins formed at the metamorphic hydrothermal stage: the earlier white-gray pyrite quartz veins (Q1) occur in layers and the late polymetallic sulfide quartz veins (Q2) cut the strata. By means of lithofacies observation and microthermometry, the authors carried out a detailed study of the fluid inclusions hosted by the quartz veins of the metamorphic hydrothermal stage. Combined with the preliminary findings, the authors estimated the physical and chemical conditions. Laser Raman and synchronic radiation X-ray fluorescence（SRXRF）were also used to analyze elements in the fluid inclusions. It is shown that the inclusions in the quartz veins are mainly carbonic fluid inclusions (CO2-N2±CH4) 4～37 μm in size, mostly assuming planar and ribbon distribution. There are also minor amounts of H2O-CO2 fluid inclusions associated with carbonic fluid inclusions. The experiment results of carbonic fluid inclusions show that tm,co2(solid CO2 melting temperatures) are -82.5～ -59.4℃, th, co2 (homogenization temperatures) are -40.2 ～20.3℃, and the lowest trapping temperatures are 209～459℃, that the densities range from 0.75 to 1.15 g/cm3, and that the estimated pressures are concentrated in the range of 110～540 MPa. The tests indicate that the gas and liquid ingredients in carbonic fluid inclusions mainly consist of CO2 and N2, and the minor elements are low in Cu, Zn, Pb but rich in Au. The environment for the formation of the carbonic fluid inclusions was basically consistent with the regional conditions of the orogenic belt, especially the biotite metamorphic belt. The tentative research suggests that the carbonic fluid inclusions were probably related to synorogenic metamorphism but had nothing to do with the submarine exhalation. The carbonates widely distributed in Lower Devonian Kangbutiebao Formation in the Kelan basin might have provided the main carbon sources for carbonic fluid inclusions.