Abstract: The Chuduoqu Pb-Zn deposit is a large newly found mineral deposit in Tuotuohe of Qinghai Province. Its ore-bodies occur as veins, controlled by the steep fracture that cut the carbonatite strata. The research of fluid inclusion shows that fluid inclusions are well developed in quartz, mainly in gas-liquid phase. The ore-forming fluid is characterized by medium-low temperature (160-220℃), low salinity (8%-10%NaCl) and low density (0.90-0.95 g/cm³), with pressure of 11 to 13 MPa and depth of 1.1 to 1.3 km. The δD value of the ore-forming fluid is -122.1‰ to -96.4‰ and the δ¹⁸OH₂O value is 2.1‰ to 9.5‰. Combined with the regional tectonic background, ore-forming characteristics of lead and zinc, fluid inclusions and ore fabrics, this paper summarized that Chuduoqu Pb-Zn deposit is a medium-low temperature hydrothermal vein Pb-Zn deposit controlled by fractures. This conclusion is of great academic and applied significance to improve lead-zinc ore potential in Tuotuohe area.