Chahansala gold deposit, a newly discovered gold deposit in Western Tianshan, locates in the west of Yilianhabi’erga arc-trench belt of Later Paleozoic and belongs to tectonic breccia altered rock-type. Our study about the fluid inclusions that in the mineralization stage veins indicates two types of fluid inclusions that as follows: ① two-phase liquid-vapor inclusions and ② three-phase CO2-rich inclusions. Their homogenization temperature ranged from 142℃ to 391℃ and 288℃ to 399℃, the salinity ranged from 2.24% to 7.73% and 1.22% to 2.39%, and the homogenization pressure ranged from 0.274Gpa to 16.35Gpa and 187.0Gpa to 240.7Gpa, respectively. The fluid inclusions was characterized by low-meso temperatures and low salinity, and is CO2-H2O-NaCl system. The ore-forming depth was about 1.1km. The change of ore-forming stress caused fluid immiscibility, and led to gold precipitation possibly. The δD and δ18OV-SMOW of the hydrothermal gangue mineral quartz are -92‰~ -74‰ and 11.8‰~12.6‰, respectively; the δ13CV-PDB and δ18OV-SMOW of the hydrothermal gangue mineral calcite are -8.92‰~ -8.06‰ and 13.45‰~17.18‰, respectively. These stable isotopes studies reveal that the ore-forming fluid of chahansala gold deposit was mainly composed of magmatic water, and formational water.