The Tulasu Pb-Zn deposit is one of the typical base metal deposits in the Tulasu basin, Western Tian-shan, Xinjiang. The outcropped orebody is hosted in the Late Paleozoic Dahalajunshan Formation tuff and controlled by the N-S trending tensional fault. The minerals in the ores mainly consist of galena, sphalerite, chalcopyrite, pyrite, quartz and calcite. The ores are characterized by the occurrence of filling textures in open space, including cave, drusy, comb and breccia textures. LA-ICP-MS U-Pb dating on zircons in ore-hosting tuff gave weighted average age of 372.5±4.3 Ma, indicating that the tuff resulted from the subduction of North Tianshan Ocean beneath the Yili-Central Tianshan Plate. A large amount of liquid-rich two-phase aqueous inclusions are developed in the ore-bearing quartz, with homogenization temperatures and salinities in the ranges of 130~210℃ and 8.1%~16.9% NaCl_eq, respectively. In addition, vapor-rich two-phase aqueous inclusions, vapor mono-phase inclusions and daughter mineral-bearing three-phase inclusions are locally observed. Both the fluid inclusions and ore textures show that fluid boiling and subsequent temperature decrease could be the important mechanism for the Pb-Zn precipitation. Galena has narrow δ³⁴S range of -2.2‰~0.5‰, indicating a contribution of magmatic-sourced sulfur. The ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb ratios of galena range from 18.208 to 18.264, 15.588 to 15.617 and 37.954 to 38.088, respectively, similar to those of gold deposits and ore-hosting volcanic rocks in the region, indicating that the ore-forming metals were sourced from the Dahalajunshan Formation volcanic rocks. Based on the information from geology, fluid inclusions and isotopes, the Tulasu Pb-Zn deposit is considered to be an intermediate-sulfidation epithermal deposit. For the further prospecting in the Tulasu basin, in addition to the low-sulfidation Au deposits that may occur near the identified Pb-Zn deposits, intermediate-sulfidation base metal mineralization should also be paid attention underneath the discovered low-sulfidation Au deposit and its vicinity.